NSF Proposal 2007 AwardNum0653570
Physics Program
\hspace{0.5in}The Q$_{weak}$ experiment and the measurement of $A_1$ at large $x$ 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 Q$_{weak}$ experiment is to measure the weak mixing angle sin$^2$($\theta_W$), the PI has found an opportunity to use the same apparatus to measure a new low energy fundamental constant known as $d_{\Delta}$ described below. Such an experiment using the Q$_{weak}$ apparatus would require 1 week to measure an inelastic parity-violating asymmetry which is an order of magnitude larger than the Q$_{weak}$ asymmetry. While a postdoctoral researcher based at Jefferson Lab, the PI began developing a program to measure the polarized to unpolarized down quark distribution ($\frac{\Delta
d}{d}$) 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$_{weak}$
\hspace{0.5in}The Q$_{weak}$ experiment (E05-008) will use parity violating (PV) electron-proton scattering at very low momentum transfers $(Q^2 \sim 0.03$~GeV$^2$) to measure the weak mixing angle sin$^2$($\theta_W$). The dominant contribution to the PV asymmetry measured by Q$_{weak}$ 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 provide a precision 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 considered a new initiative for the future of Jefferson Lab, about which the JLab Program Advisory Committee (PAC) wrote ``The PAC is very impressed with the discovery potential of this experiment and regards it as an important addition to the Jefferson Lab program. The role of the principal investigator in this program is described in section~\ref{section:QweakDetector}. A brief description of the physics is given below.
The PV asymmetry measured by inclusive electron scattering reactions is driven by the exchange of a neutral weak Z$^0$ boson. The asymmetry is amplified by the interference between the weak and electromagnetic interactions, a feature that has been exploited as a means for determining the strange quark contribution to ground state nucleon properties~\cite{Be01}. The asymmetry may be expressed as \begin{eqnarray} ~\cite{ReyaSchilcher74}, \label{eq:PVelasticAsym} \end{eqnarray} where $\sigma _+(\sigma_-)$ is the cross section for the elastic scattering of electrons of positive (negative) helicity, $\tau$, $\varepsilon$, and $\varepsilon ^{\prime}$ are kinematic factors depending on $Q^2$, $M$ is the mass of the proton, $G_F$ is the Fermi coupling constant, $\alpha$ is the electromagnetic coupling constant, $Q^2$ is the square of the four momentum transfer, $\sin ^2 \theta _W$ is the weak mixing angle, $\theta _e$ is the electron laboratory scattering angle, and $\sigma _p$ is the Mott cross section. The Sachs electromagnetic and neutral weak electric and magnetic form factors $G^{\gamma
,Z}_{E}$ and $G^{\gamma ,Z}_{M}$, respectively,
as well as the nucleon axial vector form factor $G^{Z}_{A}$, can each be expressed in terms of individual quark distribution functions. A system of equations is constructed within this framework which describes the extraction of the strange quark contribution to the electric and magnetic form factors of the nucleon, $G^{s}_{E}$ and $G^{s}_{M}$, as well as the axial form factor $G_A^Z$~\cite{Kap88} from the asymmetry measurements made.
The limit $\theta
\rightarrow 0$, $\epsilon \rightarrow 1$,
and $\tau \ll 1$, in Eq.~\ref{eq:PVelasticAsym} is taken in order
to see how a measurement of the PV asymmetry in elastic
electron-proton
scattering at very low $Q^2$ and very small electron scattering
angles can be used to test the
Standard Model.
The resulting asymmetry becomes:
\begin{eqnarray}
,
\end{eqnarray}
where $F^p$ is a form factor. Neglecting radiative corrections,
the leading term in this equation
is simply $Q_W^p = 1-4\sin ^2 \theta _W$. The $B(Q^2 )$ is the
leading term in the nucleon
structure defined in terms of neutron and proton electromagnetic
and weak form factors.
The contributions contained in $B(Q^2 )$
(which enters to order $Q^4$)
can be reduced by going to lower $Q^2$ values; however, this also
reduces the sensitivity
to $Q_W^p$ (which enters to leading order in $Q^2$) making it
statistically more difficult
to measure.
The value of $B(Q^2 )$ can be determined
experimentally by extrapolating measurements made by
the ongoing program of forward angle PV experiments at higher
$Q^2$~\cite{HAPEX,G0,A4}.
The optimum value of $Q^2$ to minimize hadron structure
uncertainties and at the same
time maximize our sensitivity to $Q_W^p$ is estimated to be near
$Q^2 = 0.03$~(GeV/c)$^2$
\cite{Qweak}.
\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 Q$_{weak}$ experiment (Q$_W(p)$~\cite{Qweak}. } \label{fig:newphysics} \end{figure}
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.
Measuring $d_{\Delta}$ using the PV $N\rightarrow \Delta$ Transition at Low $Q^2$
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.
The PI submitted a Letter of Intent (LOI-03-105) to JLab PAC24 which outlined an experiment to measure $d_{\Delta}$ using the $Q_{weak}$ apparatus \cite{Qweak}. As shown in Figure~\ref{fig:N2Delta_Asym}, a statistical precision of $<$ 0.1 ppm can be achieved at a $Q^2$ value of 0.028 GeV$^2$ in less than a week. The favorable reviews received have encouraged the PI to submit a full proposal once the Q$_{weak}$ run schedule has become firm.
\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}
The Longitudinal Spin Structure of the Nucleon
\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 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.
==Detector Development==\label{section:QweakDetector}
\hspace{0.5in}Support from this proposal will be used to
develop the Region 1 Tracking system for the Q$_{weak}$ experiment
at Jefferson Lab. Dr. Forest was
awarded a grant under the Major
Research Instrumentation (MRI) program ( Proposal \#PHYS-0321197)
to develop this tracking system.
A prototype detector and a
detector positioning system have already been built using support
from a previous NSF grant in combination with the instrumentation
support from the MRI grant.
As a result of this work, the final design has been completed
which will
construct ionization chambers
equipped
with Gas Electron Multipliers (GEM)~\cite{Sauli}
as the first tracking
element in the Qweak tracking system. The use of GEM
preamplifiers increases the rate capabilities of the chambers
allowing them to be used close to the target. As
work package manager of the Region 1 tracking system, Dr. Forest
is responsible for the construction, testing and installation of
this tracking system.
A prototype detector was built and calibrated by Dr. Forest and his physics student Jeremy Dobbins in early 2004. The detector, shown in Figure~\ref{fig:QweakProducts} was a 2cm thick ionization chamber equipped with three gas electron multiplier preamplification stages~\cite{Sauli} and having an active area of 10cm x 10cm. The detector gain of 10$^5$ and a response uniformity less than 1\% was observed which is consistent with the findings of other groups. The detectors output signal was observed to have a 25ns rise time making it ideal for use in the high rate environment expected in the Q$_{weak}$ experiment. The effect of gas pressure on the detector's gain and quantum efficiency was then quantified by Louisiana Tech graduate student Jena Kraft in her M.S. physics thesis of Nov. 2004. It was discovered during operation of the first prototype that the wire bonds used to connect the charge collection strips to 24 pin output connectors were unreliable and too fragile. As a result, the detector was redesigned to eliminate the need for these wire bonds. Preliminary testing of the new design has shown no degradation of detector performance.
\begin{figure}[htbp] \centerline{ \scalebox{0.3} [0.49]{\rotatebox{0}{\includegraphics{Graphs/Glue2DchargeCollectr_1stPrototype.eps}}} \scalebox{0.7} [0.7]{\rotatebox{0}{\includegraphics{Graphs/QweakRotatorPicture.eps}}} } \caption{A prototype Region 1 ionization chamber (left) and the support structure (right) to be used to position the tracking system for Qweak. The left image shows an ionization chamber and readout board only. Rows of black 20 pin connectors are now wave soldered directly to the readout board replacing fragile wire bonds used previously. The right image shows the detector rotation system composed of a main aluminum rotation ring upon which two liner bi-slide systems are mounted. A oil impregnated brass worm gear, underneath the main aluminum ring, is remotely controlled to turn the ring to a desired octant.} \label{fig:QweakProducts} \end{figure}
Dr. Forest assembled a team of 5 undergraduate engineering students, listed in Table~\ref{table:paststudents}, to design and construct the positioning system for the Region 1 tracking system detectors The device, shown in Figure~\ref{fig:QweakProducts}, will remotely move a pair of detectors into position as well as rotate the detectors 180 degrees. The detectors are mounted 180 degrees apart in order to position tracking elements in two octants on opposite sides of the beam. The system can rotate the detectors to a given angle with an accuracy of 1 mrad. The Bi-slide linear positioning system can move the detectors into position remotely to an accuracy of 1/2 mm and have the range to remotely move the detectors out of the Q$_{weak}$ acceptance when not needed for calibration. Pins will be used to ensure that the detectors are consistently positioned at precise locations for calibration runs.
\hspace{0.5in}Despite the above successes, continuing the research project at Louisiana Tech became problematic when the Physics graduate program was cancelled by the Louisiana Board of Regents due to the small number of graduates. The remaining work on the tracking system will involve digital readout of the detector and commissioning. The complexity of these tasks are more aligned with the typical role taken by graduate students. As a result it would have been be a real challenge to complete the project with no graduate student manpower. My new position at Idaho State University is in a Physics department which has an annual influx of over 10 graduate students per year and an average population of over 50 students. In addition to this large potential workforce, the Idaho Accelerator Center, described below under facilities, houses an electron accelerator which may be used to test the Qweak detector as well as a staffed machine and electronics shop for detector construction and instrumentation. This infrastructure will be instrumental in completing the construction and testing of the Q$_{weak}$ Region 1 tracking system.
Funds from this proposal will be used to continue the development of the detector readout system, construct the final detector, and continue testing detector performance. We are currently working to upgrade our readout system to accommodate the high rate capabilities of the detector. The VFAT chip, designed for use in the TOTEM experiment, will be used to readout the GEM detector. The VFAT board has been successfully tested on the bench and will be tested with beam this Fall. Dr. Forest will use startup funds from his new position to travel to CERN for a beam test of the TOTEM GEM based detector using the VFAT electronics. The final Q$_{weak}$ readout board will be designed to accept the standard VFAT readout cards used in TOTEM. The Idaho Accelerator Center has agreed to provide beamtime to measure the high rate capabilities of the final Q$_{weak}$ Region 1 tracking system. Graduate students as well as undergraduate students supported by this grant will receive hands on experience from the starting phase of detector construction to the operation phase at the Idaho Accelerator Center.
Prior and Future use of NSF Funds
\hspace{0.5in}While at Louisiana Tech University, the PI 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. The status of the work supported by the above awards which the PI was responsible for is given in section~\ref{section:QweakDetector} and shown in Figure~\ref{fig:QweakProducts}.
In making the transition to Idaho State University, Dr. Forest now has a pool of over 50 Ph.D. students as well as a support staff of machinists and electricians to draw upon. Funds from this proposal will be used to support a Ph.D. student and the PI's work to complete the Region 1 tracking system for Q$_{weak}$. A Ph.D. student joining this project in the Summer of 2007 will be well timed with just three years remaining until the Q$_{weak}$ experiment is scheduled to run in Hall C at Jefferson Lab. The Ph.D. student's thesis would report on the construction and instrumentation of the detector system. The student's thesis would also report on the detector performance measurements made using the Idaho Accelerator Center's high current electron accelerator. Tracking software will be put in place by the student for these studies which can be transitioned into the Q$_{weak}$ tracking software.
\begin{figure}[htbp]
\centerline{
\scalebox{0.5} [0.5]{\rotatebox{0}{\includegraphics{Graphs/RII_DC.xfig.eps}}}
}
\caption{The Region II drift chamber basic design concept
for Hall B. The horizontal wires have a pitch of 6 degrees to the horizon. }
\label{fig:RIIhallB} \end{figure}
As the Q$_{weak}$ tracking system nears completion, focus will shift to the development of other detector systems needed by Jefferson Lab. Our present interest involves the development and proto-typing of the Region II drift chamber for the Hall-B 12 GeV upgrade. The strategic plan of the physics department at Idaho State University wishes to maintain its focus on Nuclear Physics by investing in a detector development lab. This strategy is meant to enhance the capabilities of the Idaho Accelerator Center as well as support initiatives to develop an Advanced Imaging Center. The design and prototyping the Region II drift chambers for Hall B can be easily accomplished in such an environment. Phil Cole and Dan Dale, each experienced in drift chamber construction, will also take an active role developing the Hall B chambers. The group is currently participating in the Hall B tracking meetings and has created the basic design concept shown in Figure~\ref{fig:RIIhallB}. Our expectations are that a group of undergraduates would be involved in the renovation of our lab space to a clean room environment and that future graduate students would take on the task of designing and constructing the first proto-type drift chamber as part of their thesis project.
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
Undergraduates in Research
\hspace{0.5in}The PI has a history of successfully involving undergraduates in research. Table~\ref{table:paststudents} shows a list of students and their role in previous research projects. I found that students given well defined and focused task are able to gain experiences and have a positive impact on research. While my first experience involved only one physics student and resulted in a prototype detector, my most recent experience involved an interdisciplinary team of undergraduate students given the task of constructing a system to remotely rotate the Q$_{weak}$ detectors. The team of students accepted the task as part of their senior engineering project. The result, shown in Figure~\ref{fig:QweakProducts}, was a system capable of remotely rotating the Q$_{weak}$ detectors 180 degrees and position the detectors in or out of the acceptance. Each member of the team was able list the skill sets used on the project as an experience in engineering on their resumes for perspective employers to see improving their marketability as a result. The projects supported by this proposal will continue to encourage the involvement of undergraduates in research. Undergraduates involved in this work over the summer can expect to gain experience testing the Q$_{weak}$ detector in the IAC beam line.
\begin{table}[h] \begin{center} \begin{tabular}{lll} \multicolumn{1}{r}{Student}& \multicolumn{1}{c}{Major (Year of Degree)}& \multicolumn{1}{c}{Project}\\ \hline\hline Josh Anderson & B.S. EE (2005)& Qweak Rotator Controller \\ Adam Barham & B.S. ME (2005) & Qweak Rotator Mechanical Design\\ Justin Mitchell & B.S. ME (2005) & Qweak Rotator Design\\ William Stanton Martin & B.S. ME (2005) & Qweak Rotator Construction\\ Jessica Tucker & B.S. EE (2005) & Qweak Rotator Control Motors\\ Jena Kraft & M.S. Physics (2004) & GEM Detector Performance Tests\\ Jeremy Dobbins & B.S. Physics (2004) & Qweak Protoype Detector Construction\\ Maria Novovic & M.S. Physics (2003) & Qweak lucite detector tests\\ \hline \end{tabular} \end{center} \caption{A list of the PI's previous students and their projects.} \label{table:paststudents} \end{table}
Graduate Student Training and Marketability
\hspace{0.5in}Despite the small graduate student population, the PI was able to mentor two graduate students, Maria Novovic and Jena Kraft, prior to joining the Intermediate Energy Nuclear Physics Group at Idaho State University. Maria Novovic was trained in data acquisition, scintillator construction, and data analysis. She is currently a staff physicist at the University of Southern Alabama and is responsible for the undergraduate physics laboratories in addition to her undergraduate instructor role. The graduate training and experiences in Dr. Forest's lab were instrumental in securing her current position. Jena Kraft, who found a position in industry, reported that her design skills acquired while making a high pressure gas chamber for the GEM detector during her thesis were a key ingredient to her current position. The detector construction and instrumentation projects described in this proposal will continue to be effective in training graduate students for the market place.
The Intermediate Energy Nuclear Physics Group at Idaho State University currently has three graduate students, listed in table~\ref{table:currentstudents}, working on JLAB physics. This is an impressive accomplishment given that Phil Cole's current NSF grant is nearing the end of its first fiscal year. Our expectation is that this number will increase with this years addition of two faculty with JLAB projects and the annual influx of more than 10 incoming graduate students per year.
\begin{table}[h]
\begin{center}
\begin{tabular}{lll}
\multicolumn{1}{r}{Student}&
\multicolumn{1}{c}{Major }&
\multicolumn{1}{c}{Project}\\
\hline\hline
Julian Salamanca & Ph.D. & g8b\\
Davit Abrahamyan & Ph.D. & g8b\\
Oleksiy Kosinov & Ph.D. & PRIMEX \\
\hline
\end{tabular}
\end{center}
\caption{A current list of the Intermediate Energy Nuclear Physics Group's students
and their projects.}
\label{table:currentstudents}
\end{table}
Students from the Americas
\hspace{0.5in}The group has an established history of strengthening ties with Latin an South America which spans 6 years and 5 modest NSF grants totaling \$100,000~\cite{PhilsNSFAward}. Three nuclear physics symposium were held in Columbia, Mexico, and Brazil designed to attract bright young talent from the Americas into the nuclear physics program. More than five students have been recruited to pursue advanced physics degrees so far. These students are able to help satisfy the demands of research institutions which have already invested in collecting experimental data that possess an abundance of thesis topics but a limited number of students. As a result, one is able to reap returns on past investments in beam time with a small investment in manpower. These bridges of cooperation, while providing a means for recruiting high-caliber advanced students and researchers, also create an avenue for collaboration.
\begin{thebibliography}{5}
\bibitem{Qweak} Q$_{weak}$ Experiment, JLab Experiment E05-008,
R. Carlini spokesman (www.jlab.org/Qweak).
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