2008 NSF Proposal
NSF Proposal Guide
d. Project Description (including Results from Prior NSF Support)
(i) Content
All proposals to NSF will be reviewed utilizing the two merit review criteria described in greater length in GPG Chapter III.
The Project Description should provide a clear statement of the work to be undertaken and must include: objectives for the period of the proposed work and expected significance; relation to longer-term goals of the PI's project; and relation to the present state of knowledge in the field, to work in progress by the PI under other support and to work in progress elsewhere.
The Project Description should outline the general plan of work, including the broad design of activities to be undertaken, and, where appropriate, provide a clear description of experimental methods and procedures and plans for preservation, documentation, and sharing of data, samples, physical collections, curriculum materials and other related research and education products. It must describe as an integral part of the narrative, the broader impacts resulting from the proposed activities, addressing one or more of the following as appropriate for the project: how the project will integrate research and education by advancing discovery and understanding while at the same time promoting teaching, training, and learning; ways in which the proposed activity will broaden the participation of underrepresented groups (e.g., gender, ethnicity, disability, geographic, etc.); how the project will enhance the infrastructure for research and/or education, such as facilities, instrumentation, networks, and partnerships; how the results of the project will be disseminated broadly to enhance scientific and technological understanding; and potential benefits of the proposed activity to society at large.
Project Summary
The PI's in this proposal, while being a newly formed group, have an established program in experimental nuclear physics based at Jefferson Lab which seeks to perform measurements that contribute to an understanding of hadronic interactions. The impact the measurements made within this program to our present state of knowledge in this field is described in the section ~\ref{sect:IntellectualMerits}.
The group plans to continue to capitalize on it's recruitment of graduate students from the Americas, established by Dr. Cole using previous NSF awards, by training the students from this underrepresented geographic group in our proposed activities of detector development described by our work plan in section ~\ref{sect:WorkPlan}.
Intellectual Merit
Broader Impacts
Intellectual Merit of the Proposed Activity
The ISU Physics Program
The experiment and the measurement of at large in Jefferson Lab's Hall B represent the main components of the principal investigator's physics program. Both components are the continuation of the PI's previous work in parity violating electron scattering as a Ph.D. student and polarized structure functions as a postdoctoral researcher based at Jefferson Lab. While the main goal of the experiment is to measure the weak mixing angle (), the PI has found an opportunity to use the same apparatus to measure a new low energy fundamental constant known as described below. Such an experiment using the apparatus would require 1 week to measure an inelastic parity-violating asymmetry which is an order of magnitude larger than the asymmetry. While a postdoctoral researcher based at Jefferson Lab, the PI began developing a program to measure the polarized to unpolarized down quark distribution () in the nucleon. The program was recently awarded 80 days of beam time by Jefferson Lab's PAC 30. Further details of the physics program are given in the subsections below.
Q_{weak}
The experiment (E05-008) will use parity violating (PV) electron-proton scattering at very low momentum transfers to measure the weak mixing angle . The dominant contribution to the PV asymmetry measured by is given by the weak charge of the proton, $Q_W^p = 1-4\sin ^2 \theta _W$, with small corrections at order $Q^4$ from nucleon electromagnetic form factors. This measurement will be a standard model test of the running of the electroweak coupling constant sin$^2$($\theta_W$). Any significant deviation of $\sin ^2 \theta _W$ from the standard model prediction at low $Q^2$ would be a signal of new physics, whereas agreement would place new and significant constraints on possible standard model extensions including new physics. The experiment is scheduled for installation in the beginning of 2010. The role of the principal investigator in this program is described in section~\ref{section:QweakDetector}. A brief description of the physics behind the Qweak experiment is given below.
An essential prediction of the Standard Model is the variation of $\sin ^2 \theta _W$ with $Q^2$, often referred to as the ``running of $\sin ^2 \theta _W$. Testing this prediction requires a set of precision measurements at a variety of $Q^2$ points, with sufficiently small and well understood theoretical uncertainties associated with the extraction of $\sin ^2 \theta _W$. It also requires a careful evaluation of the radiative corrections to $\sin ^2 \theta _W$ in the context of the renormalization group evolution (RGE) of the gauge couplings. Such tests have been crucial in establishing QCD as the correct theory of strong interactions \cite{Hin00}, and the RGE evolution of the QED coupling has also been demonstrated experimentally \cite{TOP97,VEN98,OPAL00,L300}. The gauge coupling of the weak interaction, however, represented at low energies by the weak mixing angle $\sin ^2 \theta _W$, has not yet been studied successfully in this respect.
Shown in Fig.~\ref{fig:newphysics} is the Standard Model prediction in a particular scheme \cite{QweakAp} for $\sin ^2 \theta _W$ versus $Q^2$ along with existing and proposed world data. As seen in this figure, the very precise measurements near the $Z^0$ pole merely set the overall magnitude of the curve; to test its shape one needs precise off-peak measurements. To date, there are only three off-peak measurements of $\sin ^2 \theta _W$ which test the running at a significant level: one from APV~\cite{APV}, one from high energy neutrino-nucleus scattering~\cite{NuTeV}, and the recently completed SLAC experiment E-158(Q$_w$(e))~\cite{E158}. The measurement of $Q_W^p$ described here will be performed with smaller statistical and systematic errors and has a much cleaner theoretical interpretation than existing low $Q^2$ data. In addition, this measurement resides in the semi-leptonic sector, and is therefore complimentary to experiment E-158 at SLAC, which has determined $\sin ^2 \theta _W$ from PV $\vec e e$ (Moller) scattering (which resides in the pure leptonic sector) to roughly a factor of two less precision at low $Q^2$ \cite{E158}. The total statistical and systematic error anticipated on $Q_W^p$ from these measurements is around 4\% \cite{Qweak}, corresponding to an uncertainty in $\sin ^2 \theta _W$ of $\pm$0.0007, and would establish the difference in radiative corrections between $\sin ^2 \theta _W (Q^2 \approx 0)$ and $\sin ^2 \theta _W (M_Z )$ as a 10 standard deviation effect.
\begin{figure}[htbp] %\vspace{-1in} \centerline{ \scalebox{0.5} [0.5]{\includegraphics{Graphs/s2w_2004_4_new_2.eps}}} \caption{The dependence of $\sin^2 \theta_W$ as a function of $Q^2$ cast in the MS bar scheme by reference~\cite{Erler}. The solid line represents the Standard Model prediction. The results from three experiments (APV~\cite{APV}, $Q_W(e)$~\cite{E158}, $\nu$-DIS~\cite{NuTeV} ,Z-pole~\cite{Zpole} are shown together with the expected precision from the experiment (Q$_W(p)$~\cite{Qweak}. } \label{fig:newphysics} \end{figure}
\subsubsection{ISU's role in Qweak}
Dr. Forest is currently the work package manager of the Region 1 Detector and Front End electronics for Qweak. The detectors for the region 1 tracking system are being assembled and will be tested by the end of 2008. A front end electronics system from CERN has been chosen to digitize the analog output of the detectors. Dr. Forest has been using his start up funds to develop the infrastructure needed to implement this system in Qweak. The support from this proposal will be used to complete the front end electronics installation and maintain the region 1 tracking system during the calibration phase of the Qweak experimental currently scheduled to begin installation in JLab's Hall \ C in early 2010.
Dr. Forest submitted a Letter of Intent (LOI-03-105) to JLab PAC24 which outlined an experiment to measure $d_{\Delta}$, shown in Figure~\ref{fig:N2Delta_Asym}, using the $Q_{weak}$ apparatus \cite{Qweak} to statistical precision of $<$ 0.1 ppm in less than a week. Interest in inelastic PV physics has been bolstered by the discovery of a new radiative correction for the PV $N\rightarrow \Delta$ transition~\cite{Zhu012} resulting in a $Q^2$ independent asymmetry that does not contribute to elastic PV electron scattering. The result is a non-vanishing PV asymmetry at $Q^2 = 0$ . The new correction is the result of a photon coupling to a PV hadron vertex and is referred to as the so called ``anapole contribution which has no analog in the elastic channel. The authors in Ref.~\cite{Zhu012} use Siegert's theorem to show that the $Q^2$ independence is the result of a cancellation of the 1/$Q^2$ term from the photon propagator and the leading $Q^2$ dependence from the anapole term. The leading component from the contribution of this transition amplitude is proportional to $\omega ~(\omega = E_f -E_i )$ times the PV electric dipole matrix element and is characterized by a low energy constant $d_{\Delta}$. A measurement of the PV asymmetry in the $N\rightarrow \Delta$ transition at the photon point, or at very low $Q^2$, henceforth called the Siegert contribution, would provide a direct measurement of the low energy constant $d_{\Delta}$.
The low energy constant $d_{\Delta}$ is a fundamental constant which has implications to other long standing physics questions. The same PV electric dipole matrix element which results in $d_{\Delta}$ also drives the asymmetry parameter ($\alpha_{\gamma}$) in radiative hyperon decays, e.g. $\Sigma ^+ \rightarrow p\gamma$. Although Hara's theorem \cite{Hara64} predicts that the asymmetry parameter ( $\alpha_{\gamma}(\Sigma ^+ \rightarrow p\gamma$)) should vanish in the exact SU(3) limit, the Particle Data Group~\cite{PDGAlphaSigma} reports a measured value of $\alpha_{\gamma}(\Sigma ^+ \rightarrow p\gamma) =$-0.72$\pm$ 0.08. While typical SU(3) breaking effects are of order $(m_s - m_u )/1$GeV $\sim$ 15\%, the above asymmetry parameter is experimentally found to be more than four times larger. A solution proposed by the authors of Ref.~\cite{Bor99} involves including high mass intermediate state resonances $(1/2 ^- )$, where the weak Lagrangian allows the coupling of both the hyperon and daughter nucleon to the intermediate state resonances, driving the asymmetry parameter to large negative values. This same reaction mechanism was also shown to simultaneously reproduce the $s-$ and $p-$ wave amplitudes in non-leptonic hyperon decays, which has also been a long standing puzzle in hyperon decay physics. If the same underlying dynamics is present in the non-strange sector ($\Delta S = 0$) as in the strangeness changing sector ($\Delta S = 1$), one would expect $d_{\Delta}$ to be enhanced over its natural scale ($g_{\pi}$ = 3.8$\times 10^{-8}$, corresponding to the scale of charged current hadronic PV effects \cite{Des80,Zhu00}). The authors of Reference\cite{Zhu012} estimate that this enhancement may be as large as a factor of 100, corresponding to an asymmetry of $\sim$ 4 ppm, comparable to the size of the effects due to the axial response and therefore easily measurable. Thus, a measurement of this quantity could provide a window into the underlying dynamics of the unexpectedly large QCD symmetry breaking effects seen in hyperon decays.
\begin{figure}[htbp] \begin{center}{ %\scalebox{0.4}[0.3]{\rotatebox{-90}{\includegraphics{Graphs/N2Delta_Asym.eps}}} \scalebox{0.4} [0.4]{\includegraphics{Graphs/A_d_Delta_Prec.xfig.eps}} } \caption{Expected precision of the measured asymmetry using the Q$_{weak}$ apparatus compared with the expected asymmetry for several values of the low energy constant $d_{\Delta}$. The rectangular box indicates both the Q$^2$ bin and the asymmetry uncertainty.} \label{fig:N2Delta_Asym} \end{center} \end{figure}
Vector Meson and Hyperon Photoproduction with Linearly Polarized Photons
The probe afforded by a beam of linearly-polarized photons allows one to gain access to several observables in photonucleon reactions, which otherwise would not be measureable. The polarization axis defines a unique direction in space whereby the angular distributions of the final-state particles can be uniquely referenced. In essence, a beam of linearly-polarized photons cuts down on the glare. The polarization axis of the photon beam breaks the azimuthal symmetry of the reaction, thereby introducing an azimuthal ($\Phi$) dependence in the differential cross section. This additional information on the angular dependence opens the door to the measurement of a host of observables which are accessible only with a beam of linearly-polarized photons; consequently it provides important constraints on the nature of the photon-nucleon reaction. Such polarization observables are necessary for extracting the spin/parity of the broadly overlapping baryon resonances and measuring such parameters over a large energy range with full angular coverage is crucial for disentangling such contributions
CoPI Cole is the contact person of the experiments which comprise the g8
run \cite{Cole94,Ted98,FKlein99,Sanabria01,Pasyukg8,g8papers}.
The scientific purpose of g8 is to improve the understanding of the
underlying symmetry of the quark degrees of freedom in the nucleon, the
nature of the parity exchange between the incident photon and the target
nucleon, and the mechanism of associated strangeness production in
electromagnetic reactions. With the high-quality beam of the tagged and
collimated linearly-polarized photons and the nearly complete angular
coverage of the Hall-B spectrometer, we seek to extract the differential
cross sections and polarization observables for the photoproduction of
vector mesons and kaons at photon energies ranging between 1.10 and 2.20~GeV.
In preparation for the g8a run, we commissioned the Coherent Bremsstrahlung Facility, which was essentially a new beamline in Hall B for producing a tagged and collimated beam of linearly polarized photons, where the mean polarization in the energy range of 1.8 to 2.2~GeV was 71\%. We enjoyed a reasonably successful two-month run for g8a, which so far, has culminated in two PhD theses~\cite{CGordon, JMelone}, two master's theses~\cite{APuga, JSalamanca}, and one of the two NSF graduate research fellowships~\cite{RMammei} awarded in nuclear physics in 2003.
We seek to build upon our earlier work and investigate the nature of resonant baryon states by probing protons with polarized photons. The set of experiments forming the first phase of the g8 run took place in the summer of 2001 (6/04/01 - 8/13/01) in Hall B of Jefferson Lab. These experiments made use of a beam of linearly-polarized photons produced through coherent bremsstrahlung and represents the first time such a probe was employed at Jefferson Lab. The second time this probe was used took place in the summer of 2005 (6/20/05 - 9/01/05) for the second
phase of g8 (g8b), followed by g13b (3/08/07 - 6/29/07) and
g9a (10/17/07 - 2/11/08). The g8 set of experiments, therefore, was a vital first step for establishing the Coherent Bremsstrahlung Facility and this experience paved the way for the successful runs with linearly polarized photons in Hall B of JLab: g13b ($\vec{\gamma}d$), and g9a ($\vec{\gamma}\vec{p}$). The lessons learned in calibration and cooking for g8b have accelerated the analyses for the g13a/b and g9a. And in the three years since the end of the g8b run, we have generated or are near completion of three PhD theses: a) Craig Paterson~\cite{Paterson-g8b}, University of Glasgow, $\vec{\gamma}p \rightarrow K\Lambda, K\Sigma^{\circ}$, Aug.~2008), b) Patrick Collins~\cite{Collins-g8b}, Arizona State University, $ \vec{\gamma}p \rightarrow p\eta, p\eta^{\prime}$, Nov.~2008, and c) Juli\'{a}n Salamanca~\cite{Salamanca-g8b,LASNPA-7}, Idaho State University, $\vec{\gamma}p \rightarrow p\phi$, May~2009. \\
\medskip
\noindent \underline{\bf Photoproduction of the $\phi(1020)$} \\
Vector meson photoproduction at high energies, as is well known, is proceeds primarily through pomeron exchange rather by $\pi$ or $\eta$ meson exchange, which are respectively termed natural and unnatural parity exchange. In the baryon resonance energy regime ($\sim E_{\vec{\gamma}}=2.0$ GeV) and at low four-momentum squared transfer, $t$, peak structure of coherent $\phi$-meson photoproduction cross section around is not well explained by a pure pomeron-exchange-based model\cite{mibe}. The extraction of the Spin Density Matrix Elements (SDMEs) from $\phi$-meson decay angular distributions will shed light on the proportion of natural and unnatural parity exchange involved in the reaction mechanism\cite{shilling} at low $t$, which is further to be compared to the predicted values of the Vector Dominance Model (VDM)~\cite{sakurai}. This is to say besides the approximately 2700 (3700) $\phi$s in the energy range of $2.02 < \sqrt{s} < 2.11$ GeV ( $2.11 < \sqrt{s} < 2.20$~GeV) in the low-$t$ regime i.e.~$|t - t_{\rm min}| < 0.6$~GeV$^2$, we have approximately 700 (1700) $\phi$ mesons in these respective energy ranges for the central, non-VDM regime, i.e.~$|t - t_{\rm min}| > 0.6$~GeV$^2$. And outside this g8b dataset, there are no photoproduced phi mesons with linearly polarized photons measured in the central region in the world data set. Extracting the SDMEs for the phi channel at high $|t|$ will therefore hold discovery potential for non-VDM mechanisms at higher four-momentum squared transfers.
After making the necessary momentum, timing, particle ID, and Dalitz mass cuts we separate the data into unpolarized (AMO), perpendicular (PERP) polarization and parallel (PARA) polarization. We fit a Breit-Wigner to the phi meson peak (constrained with a decay width $\Gamma$ of 4.26~GeV with a second-order polynomial for fitting the background and a gaussian for representing the detector uncertainties. Below we display the phi peak obtained from extracting the $K^-$ from missing mass and then forming the invariant mass of the $K^+K^-$ separated in PERP and PARA orientations for the cms energy of $2.11 < \sqrt{s} < 2.20$~GeV.
\begin{figure}[h!] \begin{center} \includegraphics[height=.18\textheight]{phi_mass_para_perp.eps} \caption{\small $K^+K^-$ invariant mass in the cms energy range of $2.11 < \sqrt{s} < 2.20$~GeV fit with a Breit-Wigner + Gaussian + 2nd order polynomial. The decay width is fixed 4.26~GeV. (RHS) parallel (LHS) perpendicular polarizations.} \label{fig:phi_mass} \end{center} \end{figure}
Below we plot the combination of parallel (PARA) and perpendicular (PERP) photoproduced phi mesons for all $t$ to obtain the photon beam asymmetry parameter: $\Sigma = (W^{PARA} - W^{PERP})/(W^{PERP} + W^{PARA})$ These values are consistent with what we would expect from the Vector Dominance Model. We are presently working on separating the data into low- and high-$|t|$ regimes, but are not prepared to show it until we have authorization from the CLAS collaboration.
\begin{figure}[h!] \begin{center} \includegraphics[height=.18\textheight]{asym_all.eps} \caption{\small Beam asymmetry for the phi meson channel over the full range of $t$ for (a) $1.9 < E_{\gamma} < 2.1$~GeV and (b) $1.7 < E_{\gamma} <1.9$~GeV. The photon beam polarization is 75\%.} \label{fig:asym} \end{center} \end{figure}
Primakoff
\section{The {\em PrimEx} Experiment}
One of the Co-PI's for this proposal is a spokesperson the the {\em PrimEx} Collaboration. At present, the scientific goal of the Collaboration is to perform a high precision measurement of the neutral pion lifetime as a test of the chiral anomaly in QCD, along with different approaches to corrections to the anomaly.
The two-photon decay mode of the $\pi^{0}$ reveals one of the most profound symmetry issues in quantum chromodynamics, namely, the explicit breaking of a classical symmetry by the quantum fluctuations of the quark fields coupling to a gauge field\cite{book}. This phenomenon, called anomalous symmetry breaking, is of pure quantum mechanical origin. The axial anomaly of interest to us involves the corresponding coupling of the quarks to photons\cite{anomaly}. In the limit of exact isospin symmetry, the $\pi^{o}$ couples only to the isotriplet axial-vector current
$\bar{q}I_3\gamma_\mu \gamma_5 q$, where $q=(u,\; d)$, and
$I_3$ is the third isospin generator. If we
limit ourselves to two quark flavors, the electromagnetic current is given by $\bar{q}(1/6+ I_3/2)\gamma_\mu q$. When coupling to the photon,
the isosinglet and isotriplet components of the electromagnetic
current
lead to an anomaly that explicitly breaks the symmetry associated
with the axial-vector current
$\bar{q}\;I_3\;\gamma_\mu \gamma_5\;q$, and this in turn
directly affects the coupling of the $\pi^{o}$ to two photons. The conservation of the axial U(1) current,
to which the $\eta'$ meson couples, as well as the
$\bar{q} \frac{1}{2}\lambda_{8}\gamma_\mu \gamma_5 q$, to which the $\eta$ meson couples, are similarly affected by the electromagnetic field.
In the limit of vanishing quark masses, the anomaly leads to the
the predicted width of the $\pi^{o} \rightarrow \gamma \gamma$ decay:
\begin{equation} \Gamma=M_{\pi}^{3}\frac{ \mid A_{\gamma \gamma} \mid^{2}}{64\pi}= 7.725 \pm 0.044 eV, \end{equation}
where the reduced amplitude
\begin{equation} A_{\gamma \gamma} =\frac{\alpha_{em}}{\pi F_{\pi}} = 2.513 \cdot 10^{-2} GeV^{-1} \end{equation}
The crucial aspect of this expression is that it has no free parameters
that need to be determined phenomenologically. In addition, since the mass of
the $\pi^0$ is the smallest
in the hadron spectrum, higher order corrections to this prediction are small and
can be calculated with a
sub-percent accuracy.
The current experimental
value is $7.84 \pm 0.56$ eV\cite{PDB} and is in good agreement with the predicted value with the chiral limit amplitude. This number is an average of several experiments\cite{PDB}. Even at the 7\% level quoted by the Particle Data Book\cite{PDB}, the accuracy is not sufficient for a test of such a fundamental quantity, and in particular for the new calculations which take the finite quark masses into account. The level of precision of $\simeq 1.4\%$, which is the goal of {\em PrimEx}, will satisfy these requirements.
Stimulated by the
{\em PrimEx} project, several new theoretical calculations have been published in recent years, and are shown in figure \ref{fig:theory}. The first two independent
calculations of the chiral corrections have been performed in the
combined framework of chiral perturbation theory (ChPT) and the $1/N_c$ expansion up to ${\cal{O}}(p^6)$ and ${\cal{O}}(p^4\times 1/N_c)$ in the decay amplitude\cite{Goity}\cite{Mou02}. The $\eta'$ is explicitly included in the analysis as it plays as important a role as the $\eta$ in the mixing effects. It was found that the decay width is enhanced by about 4\% with respect to the value stated in equation (1). This enhancement is almost entirely due to the mixing effects. The result of this next-to-leading order analysis is $\Gamma_{\pi^0\to\gamma\gamma}=8.10~ {\rm eV}$ with an estimated uncertainty of less than 1\%. Another theoretical calculation based on QCD sum rules\cite{Ioffe07}, also inspired by the {\em PrimEx} experiment, has recently been published with a theoretical uncertainty less than 1.5\%. Here, the only input parameter to the calculation is the $\eta$ width. The measurement of the decay width of the $\pi^0$ with a precision comparable to these calculations will provide an important test of the fundamental QCD predictions.
File:Pio width new theory prel result.eps
\begin{figure} \centering \psfig{figure=pio_width_new_theory_prel_result.eps,height=6.0in,width=6.0in} \caption{$\pi^{o} \rightarrow \gamma \gamma$ decay width in eV. The dashed horizontal line is the leading order prediction of the axial anomaly (equation 3)\cite{book, anomaly}.The left hand side shaded band is the recent QCD sum rule prediction and the
right hand side shaded band is the next-to-leading order chiral theory predictions.
The experimental results with errors are for : (1)~the direct method\cite{At85}; (2, 3, 4)~the Primakoff method \cite{Br74,Bel70,Kr70}; (5)~the preliminary result from the first {\em PrimEx} data set; (6)~the expected error for the final goal of the {\em PrimEx} experiment, arbitrarily plotted to agree with the leading order prediction.} \label{fig:theory} \end{figure}
We are using quasi-monochromatic photons of energy 4.6-5.7~GeV
from the Hall~B photon tagging facility to measure the absolute cross section
of small angle $\pi^{o}$ photoproduction from the Coulomb field of complex
nuclei. The invariant mass and angle of the pion are reconstructed by
detecting the $\pi^{o}$ decay photons from the $\pi^{o} \rightarrow \gamma
\gamma$ reaction.
For unpolarized photons, the Primakoff cross section is given by:
\begin{equation} \frac{d\sigma_P}{d\Omega}=\Gamma_{\gamma \gamma}\frac{8{\alpha}Z^2}{m^3}\frac{\beta^3{E^4}}{Q^4}|F_{e.m.}(Q)|^ 2 sin^{2}\theta_{\pi} \end{equation}
\noindent where $\Gamma_{\gamma \gamma}$ is the pion decay width, $Z$ is the atomic number, $m$, $\beta$, $\theta_{\pi}$ are the mass, velocity and production angle of the pion, $E$ is the energy of incoming photon, $Q$ is the momentum transfer to the nucleus, and $F_{e.m.}(Q)$ is the nuclear electromagnetic form factor, corrected for final state interactions of the outgoing pion.
As the Primakoff effect is not the only mechanism for pion photoproduction at high energies, some care must be taken to isolate it from competing processes. In particular, the full cross section is given by:
\begin{equation} \frac{d\sigma}{d\Omega_{\pi}} = \frac{d \sigma_P}{d\Omega} + \frac{d\sigma_C}{d \Omega} + \frac{d \sigma_I}{d\Omega}+ 2 \cdot \sqrt{\frac{d\sigma_{P}}{d\Omega} \cdot \frac{d\sigma_{C}}{d\Omega}} cos(\phi_1 + \phi_2) \end{equation}
\noindent where the Primakoff cross section, $\frac{d \sigma_P}{d\Omega}$, is given by equation (4). The nuclear coherent cross section is given by: \begin{equation} \frac{d\sigma_C}{d \Omega} = C \cdot A^2 |F_N(Q)|^2 sin^2\theta_{\pi} \end{equation} and the incoherent cross section is: \begin{equation}
\frac{d \sigma_I}{d\Omega}=\xi A (1-G(Q)) \frac{d
\sigma_H}{d\Omega} \end{equation} where $A$ is the nucleon number, $C sin^2\theta_{\pi}$ is the square of the isospin and spin independent part of the neutral meson photoproduction amplitude on a single nucleon, $|F_N(Q)|$ is the form factor for the nuclear matter distribution in the nucleus, (corrected for final state interactions of the outgoing pion), $\xi$ is the absorption factor of the incoherently produced pions, $1-G(Q)$ is a factor which reduces the cross section at small momentum transfer due to the Pauli exclusion principle, and $\frac{d \sigma_H}{d\Omega}$ is the $\pi^o$ photoproduction cross section on a single nucleon. The relative phase between the Primakoff and nuclear coherent amplitudes without final state interactions is given by $\phi_1$, and the phase shift of the outgoing pion due to final state interactions is given by $\phi_2$.
The angular dependence of the Primakoff signal is different from the background processes, allowing $\Gamma(\pi^0\rightarrow \gamma\gamma)$ to be extracted from a fit to the angular distribution of photo-produced $\pi^0$. Measurements of the nuclear effects at larger angles are necessary to determine the unknown parameters in the production mechanism and thus make an empirical determination of the nuclear contribution in the Primakoff peak region. Consequently, this experiment uses a $\pi^{o}$ detector with good angular resolution to eliminate nuclear coherent production, and good energy resolution in the decay photon detection will enable an invariant mass cut to suppress multi-photon backgrounds.
%\begin{figure} %\centerline{\epsfxsize=200pt \epsfbox[200 150 430 500]{pb_cross_color.ps}} %\vspace{1cm} %\caption{Angular behavior of the electromagnetic and nuclear %$\pi^o$ photoproduction cross sections for %$^{208}$Pb in the 6.0~GeV energy range. } %\label{fig3} %\end{figure}
We submitted our first proposal (E-99-014) to PAC15 in December of 1998. It was approved by PAC15 and
reconfirmed in jeopardy review later by PAC22 with an ``A rating. An NSF MRI proposal for \$960k
was awarded (PIs: D. S. Dale, A. Gasparian, R. Miskimen, S. Dangoulian) for the construction of a multichannel neutral pion calorimeter. This was successfully designed, constructed, and commissioned over the period 2000-2004. The first experiment on two targets ($^{12}$C and $^{208}$Pb) was performed in 2004. The preliminary results demonstrate that we are able to control the systematic errors with the designed precision. A second run (E-08-023, spokespersons: D. Dale, A. Gasparian, M. Ito, R. Miskimen) was approved by PAC33 with an $A-$ rating for 20 days of running to reach the proposed goal of $\sim 1.4\%$ accuracy. While the Co-PI of this funding proposal has been involved in all aspects of this program, he has taken primary responsibility for the flux normalization. This has involved the design, construction, and commissioning of the {\em PrimEx} pair spectrometer. In addition,along with his students, he has been responsible to the analysis of the resulting data. This has also included a high precision measurement of the absolute cross section of a well known QED process, pair production, to verify that the flux determination was correct. To date, the co-PI has supervised to completion one Ph.D. student A. Teymurazyan) and one M.S. student on this work. One more Ph.D. student (O. Kosinov) is currently working toward his degree.
\bibitem{book} See {\sl e.g.} Dynamics of the Standard Model,
J.F. Donoghue,
E. Golowich, and B.R. Holstein, Cambridge University Press (1992).
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\bibitem{PDB} R.M. Barnett {\sl et al.}, Review of Particle Physics, Phys.
Rev. D54,1 (1996).
`
\bibitem{Goity} J. L. Goity, A. M. Bernstein, J. F. Donoghue,
and B. R. Holstein, manuscript in preparation;
J. L. Goity, talk at Baryons 2002.
\bibitem{Mou02}B. Ananthanarayan and B. Moussallam, preprint hep-ph/0205232.
\bibitem{Ioffe07}B.L. Ioffe and A.G. Oganesian, Phys. Lett. B647, (2007) 389.
\bibitem{At85} H.W. Atherton {\sl et al.}, Phys. Lett., vol. 158B, no. 1, (1985), 81.
\bibitem{Br74} A. Browman et al., Phys. Rev. Letts., vol. 33, no. 23, (1974),
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\bibitem{Bel70} G. Bellettini et al., Il Nuovo Cimento, vol. 66, no. 1, (1970), 243.
\bibitem{Kr70} V.I. Kryshkin {\sl et al.}, Sov. Phys. JETP, vol. 30, no. 6, (1970),1037.
Prior and Future use of NSF Funds
Prior use of NSF funds
The PI's in this proposal have a strong record of receiving external funding from the NSF and a history of effectively using those funds to make substantially contributions to the infrastructure of the nuclear physics program described in this proposal. The bremsstrahlung facility in JLAB's Hall-B is one example of Dr. Cole's efforts to enhance the capabilities of Hall B's photon physics program. Dr. Dale has used NSF funds to install a pair spectrometer facility in Hall B. The region 1 tracking system for Qweak was constructed by Dr. Forest using NSF funds.
While at Louisiana Tech University, Dr. Forest received three prior NSF awards as a member of the Louisiana Tech Particle Physics Group. The first proposal entitled ``Parity Violating Electron Scattering at Jefferson Lab, was awarded in 2002 for three years in the amount of \$670,230 (NSF Award \#0244998) to Louisiana Tech University. The award supported the groups efforts building triggering electronics for the G0 backward angle measurements and for the initial development of the $Q_{weak}$ experiment. The second proposal, ``Precision Electroweak Measurements at Jefferson Lab, was awarded \$204,594 in 2006 (NSF Award \#0555390) with similar support for the next two years to continuing the Lousiana Group's efforts. Dr. Forest's MRI Proposal (\#PHYS-0321197) entitled {\small ``Collaborative Research:Development of a Particle Tracking System for the Qweak Experiment} was awarded \$131,770 on July 26, 2003 to develop the Region 1 tracking system for the Q$_{weak}$ experiment. After moving to ISU, Dr. Forest recieved a grant to continue his research efforts on Qweak as well as hist work Semi-inclusive Deep Inelastic Scattering. The status of the work supported by the above awards which the Dr. Forest was responsible for is given in section~\ref{section:QweakDetector} and shown in Figure~\ref{fig:QweakProducts}
Qweak Detector Construction
The design, construction, and testing of the Region 1 tracking system for the Qweak experiment at Jefferson Lab has been the main research activity supported by Dr. Forest's previous NSF grant. The Qweak Region 1 tracking system is one of three tracking systems designed to measure the Q2 profile of elastically scattered electrons as well as background contributions to the parity violating signal. The Region 1 tracking system is located behind the first collimator at a distance of about 550 cm from the main torus magnet ( 200 cm from the target). The collimator divides the φ acceptance into 8 regions, octants, and reduces the azimuthal acceptance by almost 30 percent. The right hand figure below shows the elastic scattering profile overlayed on top of one of the octants. The Region 1 tracking system will measure the electron scattering angle at only 2 of the octants at a time and will rotate in φ to perform measurements in the remaining octants.
The high radiation flux and the small detector footprint are two of the biggest challenges facing the Region 1 tracking system. An ionization chamber equipped with Gas Electron Multipliers (GEM) was chosen in order to accommodate the high radiation flux near the target. The GEM preamplifiers allow smaller ionization cell sizes thereby resulting in ionization chamber rise times of 50 nanoseconds or less. The ionization chamber itself is constructed from Ertalyte, a machinable plastic material which can withstand the high radiation environment. The material's strength allows the chamber to have thin walls which prevent the chamber from extending into adjacent octants. The three major components to the Qweak Region 1 detector are the GEM preamplifiers, the charge collector, and the ionization chamber are describe below.
The figure below shows the custom designed GEM preamplifier for the Qweak Region 1 tracking system. The preamplifier is a 50 micron thick kapton foil clad on both sides with 5 microns of copper. Holes are etched into the foil such that a high voltage (HV) applied across the top and bottom copper plates will create an electric field strong enough to cause charge to pass through the hole and multiply much like the avalanche region of a drift chamber. Engineers from the Idaho Accelerator Center (IAC) designed the shape of the foils and the location of 6 tabs used for HV connections, as shown in the left hand figure below. This generic design allows one to use the part for any GEM amplification stage simply by cutting off the unused HV tabs. The actual preamp is shown on the right hand side of the figure below. Although this is a simple part, it is a clear example of how the infrastructure at the IAC can be leveraged in support of our physics mission.
The charge collector for Qweak's region 1 tracking system is shown below. The copper charge collector strips are aligned in terms of the electron scattering angle θ. Each of the red strips shown in the right hand figure below is 400 microns wide and will measure the elastic electron scattering angle to within 0.1 mrad. The blue lines shown in the left hand figure are representative of the φ scattering angle. A large number of graduate student hours were needed to place each strip into the correct position using PC board design software. Software compatibility issues with the vendor were also a major time sink of several months before the part could be accurately manufactured according to our specifications. This single part represents the bulk of a graduate students effort for the past 6 months and is one example of a practical component to a students educational experience. Two charge collectors have already been received but had two small errors which have been correct. Although the vendor for this part has had production difficulties resulting in delays of several months, the part and is expected to arrive by the end of October, 2008.
The ionization chamber for the Qweak Region 1 tracking system needs to have a small profile in order to be placed less than a quarter meter after the target. A collimator in front of this detector divides the electron scattering anglular range into octants which reduce the angular acceptance range by about 30 percent. The goal was to construct a chamber which did not interfere with the other octants and be transportable between octants. The figure below shows the top half of the ionization chamber which has been built. As seen in the figure, the electron profile is enclosed by the detector acceptance and the ionization chamber frame is in the shadow of the collimator. The HV distribution board has been designed by physics undergraduate student Jordan Keough and is ready to be sent out for production. Chamber construction will be completed when the charge collector arrives from the vendor and is installed. We expect to test the chamber in August, 2008.
pair spect
Brem facility
Future Use of NSF funds
The PI's in this proposal are spokepersons on experiments which require an energy upgraded JLAB and have undertaken the task of constructing the R1 drift chambers for Hall B. The future efforts will be towards completing the Qweak experiment, upgrading Hall B, and continue our efforts to increase underrepresented groups in physics from the Americas with the targeted dates shown in the timetable below.
Polarized Structure Functions
\hspace{0.5in}Spin structure functions of the nucleon have been measured in deep inelastic (DIS)lepton scattering for nearly 30 years since the first experiments at SLAC. Interest increased substantially in the 80's when the EMC collaboration reported that the quark helicities made a small contribution to the overall helicity of the proton, according to their data. This ``spin crisis led to a vigorous theoretical and experimental effort over the next 20 years, with a large data set collected at CERN, SLAC, DESY and Jefferson Lab. As of today, the data indicate that between 25\% - 35\% of the nucleon spin is carried by the quark spins, with the remainder being attributed to gluon polarization and orbital angular momentum. The world data set however, has yet to resolve whether the three valence quark spins ($uud$ in the proton) follow the ``naive expectation of relativistic quark models that 60\% -- 70\% of the nucleon spin is carried by quark helicities.
The interest in this field continues unabated as new experiments (COMPASS %~\cite{COMPASS} at CERN and the nucleon spin program at RHIC %~\cite{RHIC} ) are attempting to measure the low-$x$ gluon and sea quark polarization in a polarized nucleon with high precision. At large-$x$, new data from JLab address for the first time the question of the helicity structure of the nucleon in a kinematic realm where sea quark and gluon contributions are minimal thereby making one mostly sensitive to valence quarks. Examples of these results are shown in Fig.~\ref{delqJLab}. To extend this region to higher $x$ and moderate $Q^2$, one needs higher beam energies than presently available at JLab. In particular, to test various models of the asymptotic value of the virtual photon asymmetry $A_1(x)$ as $x \rightarrow 1$, one needs the upgraded CEBAF with 12 GeV beam energy.
\begin{figure} [!hbp] \begin{center}{ \scalebox{0.4} [0.5]{\includegraphics{Graphs/delq_new1.eps}} \scalebox{0.4} [0.5]{\includegraphics{Graphs/deltad_CLAS12.eps}} } \caption{The polarized to unpolarized up and down quark distribution ratio. The left figure shows the results from recent JLab experiments on the virtual photon asymmetry $A_1$ for the proton, Deuteron~\cite{EG2DeltaD} and neutron ($^3$He)~\cite{HallADeltaD}. The right figure represents the proposed measurements. The expected data have been draw along the pQCD and CQM prediction. } \label{delqJLab} \end{center} \end{figure}
The comprehensive data set to be
collected by experiment PR12-06-109 will contribute
substantially to our knowledge of polarized parton distribution
functions for all quark flavors and even the polarized
gluon distribution $\Delta g$. Through Next-to-Leading Order (NLO) analysis
of the world data on inclusive DIS (using the DGLAP
evolution equations), one can constrain these
distribution functions and their integrals. Existing CLAS data
from 6 GeV have already made an impact on these fits. The
expected data from the proposed experiment at 11 GeV will yield
further dramatic reductions in the errors on these distributions.
In addition, semi-inclusive DIS (SIDIS)
data will also be collected, where in addition
to the scattered electron we will detect some of the leading
hadrons produced when
the struck quark hadronizes. These data will further constrain
the NLO fits and improve the
separation of the various quark flavors' contribution to the nucleon spin.
Baryon Spectroscopy Program
CLAS 12 DC Design and Construction
The ISU physics group is currently planning to built the Region 1 drift chambers at ISU for the Hall-B 12 GeV upgrade. Three sets of azimuthally-symmetric wire chambers form the CLAS12 forward-tracking system and will have the same apt naming convention: Region 1, 2 and 3 (or R1, R2, & R3, respectively). The primary design objective is to achieve nearly full acceptance, in the lab frame, for relativistic forward-boosted final-state particles while maintaining a momentum resolution of 0.5 to 1% for a 5 GeV/c charged particle. In this document we shall focus on Region 1. Six identical R1 DCs will located 2.3 meters from the target and together will have a 2 azimuthal coverage and presently span from 5 to 45 degrees in polar angle as measured from the direction of the electron beam. The central plane through the R1 DC will be tilted 25 degrees from a perpendicular to the beam line towards the target.
File:CLAS12 ForwardDetector EPS.eps
A clean room has been designed for the purpose of constructing the R1 chambers at the IAC. A 20' by 30' by 14' high softwall clean room will be installed at the IAC which maintains at positive pressure to reduce drift chamber contaminants. An ante chamber (dimensions: 12' x 20' x 14' high) will exist along the width of the main room and will bepartitioned into two parts. One part is the dressing room and the other part will be a staging area for bringing the 8' by 8' wire chambers in and out . The curtains will be clear 40-mil thick vinyl. We require good lighting for threading the 30 μm wire into the feedthrough holes and a sufficient number of fan-filter units to maintain the Class 10,000 (ISO 7) designation, which requires an exchange of 30 air volumes per hour. The ceiling will have removable tiling, with one aluminum panel having a 2 diameter grommet to allow for a cable from the 5-ton crane overhead to enter the cleanroom. We calculate that a fully-loaded R1 DC with assembly carriage will weigh less than a ton. We expect to procure and install the clean room by the summer of 2009.
Work Plan
A work plan time line is given below which summarizes the objectives of this proposal.
| Date | Milestones |
| 06/09 | Begin installing a clean room for constructing Hall B R1 Drift Chambers at the Idaho Accelerator Center |
| 09/09 | Complete testing of the Qweak Region 1 tracking system at JLab |
| 01/10 | Begin Construction of R1 Chambers |
| 03/10 | Complete installation of Qweak Region 1 tracking system in JLab's Hall C |
| 06/10 | Quality Assurance Tests for the First R1 Drift Chambers |
| 10/12 | Install all R1 chambers in Hall-B |
| 08/09 - 07/11 | Continue efforts in establishing collaborations with nuclear physicists in Latin America through the Latin American Symposia for Nuclear Physics and Applications and further recruit students into areas of research involving JLab physics. |
| 08/09 - 07/11 | Analyze g8b and g13a/b data: omega and charged rho production. |
List of Currently supported students
| Student | Classification | Expected Grad Yr |
| Julian Salamanca | Ph. D. | 2009 |
| Tamar Didbarize | Ph. D. | 2010 |
| Danny Martinez | Ph. D. | 2012 |
| Oleksei Kosinov | Ph. D. | 2012 |
| Adrianne Spilker | M.S. | 2009 |
| Saitiniyazi Shadike | M.S. | 2009 |
| Jordan Keonough | BS | 2011 |
| Nathan Lebaron | BS | 2012 |
Facilities
\hspace{0.5in}The Idaho State University Department of Physics Strategic Plan identifies the use of experimental nuclear physics techniques as its focus area to addressing problems in both fundamental and applied science. The major efforts of the department include fundamental nuclear and particle physics, nuclear reactor fuel cycle physics, nuclear non-proliferation and homeland security, accelerator applications, radiation effects in materials and devices, biology and health physics. Because of this focus, the department has been characterized as one of the largest nuclear physics graduate programs in the nation with an average of over 50 graduate students. One of the key ingredients to the department's success has been the completion of the Idaho Accelerator Center (IAC) on April 30, 1999. A substantial amount of lab space (4000 sq. ft.) within the department has become available due to a combination of the IAC and a remodeling of the physics building. A detector lab with the potential to construct proto-type drift chambers in a clean room environment is currently planned as part of the lab space renovation.
The Idaho Accelerator Center (IAC) is located less than a mile away from campus and will provide a machining facility for detector construction, an electronics shop for installation of instrumentation, and beam time for detector performance studies. The IAC houses ten operating accelerators as well as a machine and electronics shop with a permanent staff of 8 Ph.D.'s and 6 engineers. Among its many accelerator systems, the Center houses a Linac capable of delivering 20 ns to 2 $\mu$s electron pulses with an instantaneous current of 80 mA up to an energy of 25 MeV at pulse rates up to 1kHz. The IAC has donated beam time to the Q$_{weak}$ project for the purpose of testing detector performance. One of the goals of these tests will be to evaluate the Q$_{weak}$ detector at high rates. The IAC is well suited for these rate tests as the Q$_{weak}$ calibration rates will be much lower than the electron and photon rates the IAC is capable of generating. A full description of the facility is available at the web site (www.iac.isu.edu).
The Beowulf REsource for Monte-carlo Simulations (BREMS) is a 12 node, 64 bit cluster housed in the ISU physics department which can support the high performance computing needs of the physics research program. This facility is the result of an investment made by NSF award PHYS-987453. This infrastructure will be an effective means for performing GEANT4 simulations of the Q$_{weak}$ experiment as well as Garfield simulations of the Region II drift chamber design. Simulation speed is increased on BREMS by running the simulation in parallel on many CPUs. A version of GEANT4 known as ParGeant4~\cite{ParGeant4} has recently been distributed which will allow these simulations to be run in parallel.
The Broader Impact of the Idaho State University Nuclear Physics Research Program
The Americas
Our broader impacts activities are directed towards the Americas, cental and south. Over the past nine years, the two CoPIs have have been active in outreach towards Latin America. CoPIs Dale and Cole can both communicate in Spanish. Indeed, this past year CoPI Cole successfully completed Spanish 201 and 202 at ISU, as a Freshman with an undeclared major, and he is presently enrolled in an advanced Spanish composition course at the 300-level in the effort to attain fluency. Speaking Spanish is necessary for our broader impacts activities. South American physics students tend to read English rather well, but speaking good English is entirely another matter. To attract students, one needs to present the many research opportunities in medium nuclear physics the United States while dispelling subtle and not-so-suble misconceptions, which abound. And to communicate these matters, it is imperative to speak good Spanish.
We seek to promote dialogue between faculty members of North-American and Latin-American institutions by finding common interests in research which will allow for coordinating our programs in nuclear physics research. Through this effort, we expect to strengthen existing links and forge new ones within the broad scope of the international nuclear physics community. CoPI has been a PI four times and a CoPI twice on six separate Americas Program grants, which amounts in \$130k in funding.
\medskip \begin{center} \underline{\sf Funding History} \end{center}
\begin{itemize} \item The {\sf III Latin American Workshop on Nuclear and Heavy Ion Physics} (PI: Phil Cole) NSF-INT-9907453 for \$15,000
\item {\sf A Collaborative Effort between the U.S. and Colombia on the Physics with Linearly Polarized Photons}. (PI: Phil Cole) NSF-OISE-0101815 for \$32,590.
\item {\sf Americas Program: Student Sponsorship at the Fourth Latin American Symposium on Nuclear Physics, Mexico City, Mexico, September 24-28, 2001.} (PI: Phil Cole) NSF-OISE-0117545 for \$23,369
\item {\sf US-Brazil Student Sponsorship at the Fifth Latin American Symposium on Nuclear Physics; Santos, Brazil, September 1-5, 2003}
(PI: Phil Cole, CoPI Jorge Lopez) NSF-OISE-0313656 for \$18,000
\item {\sf U.S.-Argentina Collaborative Workshop in Nuclear Physics and Its Applications} (PI: Chaden Djalali, CoPI: Phil Cole) NSF-OISE-0527110 for \$32,200.
\item {\sf US-Peru Workshop in Nuclear Physics and Its Applications, June 11-16, 2007, Cusco, Peru} (PI: Chaden Djalali, CoPI: Phil Cole) NSF-OISE-0652360 for \$32,200. See: VII Latin American Symposium on Nuclear Physics and Applications, AIP Conference Proceedings 947 (2007), Editors: Ricardo Alarcon, Philip L.~Cole, Chaden Djalali, and Fernando Umeres.
\end{itemize}
Recent outcomes of our links with the Latin American community include Mr. Tulio Rodrigues visit to Jefferson Lab in August 2004 to work with Dr.~Dan Dale on theoretical calculations for the PrimEx experiment. At the time CoPI Dale was at the University of Kentucky. Mr.~Rodrigues was supervised by Dr.~Arruda-Neto, head of the Nuclear Reactions and Structure Research Group at the Physics Institute of the University of S\~{a}o Paulo and received his PhD in 2006. Dr.~Rodrigues has visited ISU twice in the past two years to work on PrimEx-related physics. Another graduate student, Mr.~Vladimir Montealegre from the Universidad de los Andes in Bogot\'{a}, Colombia, entered the PhD program at the University of South Carolina. Our recruitment efforts are paying off. Our group now has two strong PhD students, Juli\'{a}n Salamaca and Danny Mart\'{\i}nez, from Colombia and upon processing the necessary paperwork, two more PhD students from Colombia will join us in January, 2009.
\medskip
\begin{center}
\underline{\sf The Need}
\end{center}
Lack of modern equipment is one of the main obstacles to applied research in the less-developed Latin American countries. There is, however, considerable variation in the size and influence of the physics community by individual countries ~\cite{MoranLopez}. A few groups have managed to pursue successful experimental programs in countries with comparatively long tradition in applied and basic research in the nuclear sciences; the chief examples being Argentina, Brazil, Chile, and Mexico, countries, where research is fostered through collaborative efforts through annual national nuclear physics conferences. Two of these countries Brazil, site of the V LASNP, and Argentina, site of the VI LASNPA, have launched initiatives to construct large facilities allowing for its use by the wider international nuclear physics community: the Brazilian National Synchrotron Light Laboratory (LNLS) in Campinas (about 70 miles west of S\~{a}o Paulo) and the Tandar heavy ion accelerator in Buenos Aires, Argentina. Other countries in the region which have recently initiated activities aimed to improve their academic and scientific infrastructure in the nuclear sciences include Bolivia, Colombia, Peru and Venezuela.
\medskip \begin{center} \underline{\sf The Opportunity} \end{center}
There is ample room for collaborative overlap between the two hemispheres. Establishing links between the United States and Latin America will provide a means for recruiting high-caliber graduate-level students and post-doctoral fellows to pursue research at US institutions and laboratories such as JLab, RHIC, ORNL, RIA, and IAC. Such an academic relationship between North and South America will further strengthen the scientific endeavors of the nuclear physics communities of both continents. There is at present a dearth of graduate students pursuing advanced degrees in experimental and theoretical nuclear physics at US universities. This shortage is keenly felt at the national laboratories and facilities, where there are an abundance of PhD theses topics and a paucity of graduate students. The goal is to build ties with faculty and students. While attracting students to US graduate programs, we also wish to build new groups and infrastructure in Latin America that would give the students an attractive career option in their home country after graduation.
%\newpage \medskip \begin{center} \underline{\sf The Means and the Goals} \end{center}
We seek to grow these outreach efforts and our group
will continue to write funding grants to the NSF Americas Program for sponsoring students to attend future interations of the Latin American Symposium for Nuclear Physics and Applications. CoPI Cole was recently elected to the ten-member board International Organizing Committee of the VIII Latin American Symposium on Nuclear Physics and Applications to be held in Santiago, Chile, December 15-19, 2009. As in the past, the Committee's responsibilities include the scientific program, formation of an International Advisory Board, and some key aspects of the overall organization of the Symposium. Of this membership, four members are from Universities in the United States. CoPI Cole further will write a grant to the International Atomic Energy Agency to help defray travel expenses for non-U.S.~students in Latin America, where typically funding from the NSF cannot apply.
Budget Justification
The three senior personnel on this project, Dr. Phil Cole, Dr. Dan Dale, and Dr. Tony Forest, each have established physics programs at Jefferson Lab and will continue to pursue those endeavors using the support itemized in the budget. Almost 40% of the budget in this proposal is devoted to supporting several graduate students currently pursuing their Ph. D. degrees within the JLab research program. Two undergraduate students will also continue to be supported by this grant. Undergraduates supported in past years have made substantial contributions to the program while gaining research experience. The support from this grant will be used to extend those experiences to include accelerator operations. We plan to use undergraduates as operators of the accelerators we will be using to provide ionizing radiation for testing the detectors we build.
Our travel budget is based on the number of shifts we expect to take at JLAB as well as several collaboration meetings we will need to attend. The ISU group was assigned 32 CLAS shifts in 2008 which requires at most 8 trips to JLab when the shifts are taken in blocks of 4. Our past experiences indicate that the costs of an individual trip to JLAB from Idaho range between $1,200 and $2,000 per trip. We estimate that we will spend approximately $16,000 per trip in order to absorb the market fluctuations as well as the probably increases in travel costs. Each PI expects to attend at least 3 collaboration meetings per year. The PI's have substantial roles in the Qweak, PRIMEX, and CLAS collaborations. We estimate a cost of $18,000 for this travel. We also expect to present the results of our work at conferences each year and request $4,000 to defray those costs.
A shipping budget for $100 is requested to support the exchange of materials between JLab and ISU as we move towards construction of the RI tracking system for CLAS12. Our Laboratory for Detector Science expends on average $3000 in consumables each year. We expect to upgrade or replace an average of 1 computer each year which is used for data acquisition or analysis at a cost of $2000. We will also add to our data acquisition system by purchasing a NIM/VME modules at a cost of $5000. During the first we plan to purchase two gate generators for digital signal generation and a VME module for producing LVDS signals. The LVDS signal module will be used to test the front end electronics of the Qweak Region 1 tracking system. In year two we plan on purchasing F1 TDC's for the purpose of measuring the performance of Drift Chambers developed as part of the CLAS 12 GeV upgrade. We plan on purchasing several more channels of leading edge discriminators and post amplifiers in the final year to increase the number of detector channels we are capable of measuring with out current CODA based DAQ system.