The Mu2e experiment at Fermilab will search for the neutrinoless μ−→e− conversion in the field of an aluminum nucleus. The Mu2e data-taking plan assumes two running periods, Run I and Run II, separated by an approximately two-year-long shutdown. This paper presents an estimate of the expected Mu2e Run I search sensitivity and includes a detailed discussion of the background sources, uncertainties of their prediction, analysis procedures, and the optimization of the experimental sensitivity. The expected Run I 5σ discovery sensitivity is Rμe=1.2×10−15, with a total expected background of 0.11±0.03 events. In the absence of a signal, the expected upper limit is Rμe<6.2×10−16 at 90% CL. This represents a three order of magnitude improvement over the current experimental limit of Rμe<7×10−13 at 90% CL set by the SINDRUM II experiment.

Experimental cross sections for the $^4He(e,e'p)X$ reaction up to a missing momentum of 0.632 GeV/$c$ at $x_B=1.24$ and $Q^2$=2(GeV/$c$)$^2$ are reported. The data are compared to Relativistic Distorted Wave Impulse Approximation(RDWIA) calculations for $^4He(e,e'p)^3H$ channel. Significantly more events in the triton mass region are measured for $p_{m}$$>$0.45 GeV/$c$ than are predicted by the theoretical model, suggesting that the effects of initial-state multi-nucleon correlations are stronger than expected by the RDWIA model.

The strong interaction is not well understood at low energy, or for interactions with low momentum transfer Q 2 , but one of the clearest insights we have comes from Chiral Perturbation Theory ( χ PT). This effective treatment gives testable predictions for the nucleonic generalized polarizabilities — fundamental quantities describing the nucleon’s response to an external field. We have measured the proton’s generalized spin polarizabilities in the region where χ PT is expected to be valid. Our results include the first ever data for the transverse-longitudinal spin polarizability δ LT , and also extend the coverage of the polarizability d 2 to very low Q 2 for the first time. These results were extracted from moments of the structure function g 2 , a quantity which characterizes the internal spin structure of the proton. Our experiment ran at Jefferson Lab using a polarized electron beam and a polarized solid ammonia (NH 3 ) target. The δ LT polarizability has remained a challenging quantity for χ PT to reproduce, despite its reduced sensitivity to higher resonance contributions; recent competing calculations still disagree with each other and also diverge from the measured neutron data at very low Q 2 . Our proton results provide discriminating power between existing calculations, and will help provide a better understanding of this strong QCD regime.

The strong interaction is not well understood at low energies or for interactions with low momentum transfer. Chiral perturbation theory gives testable predictions for the nucleonic generalized polarizabilities, which are fundamental quantities describing the nucleon's response to an external field. We report a measurement of the proton's generalized spin polarizabilities extracted with a polarized electron beam and a polarized solid ammonia target in the region where chiral perturbation theory is expected to be valid. The investigated structure function g2 characterizes the internal spin structure of the proton. From its moments, we extract the longitudinal–transverse spin polarizability δLT and twist-3 matrix element and polarizability $$\overline{{d}_{2}}$$ . Our results provide discriminating power between existing chiral perturbation theory calculations and will help provide a better understanding of this strong quantum chromodynamics regime. Measurements of the proton's generalized spin polarizabilities provide discriminating power between effective descriptions of the strong interaction at low energy.

Inclusive electron scattering from nuclear targets has been measured to extract the nuclear dependence of the inelastic cross section in Hall C at the Thomas Jefferson National Accelerator facility. Results are presented for 2H, 3He, 4He, 9B, 12C, 63Cu and 197Au at an incident electron beam energy of 5.77 GeV for a range of momentum transfer from Q^2 = 2 to 7 (GeV/c)^2. These data improve the precision of the existing measurements of the EMC effect in the nuclear targets at large x, and allow for more detailed examinations of the A dependence of the EMC effect.

J. Arrington, 2 J. Bane, 4 A. Daniel, 6 N. Fomin, 4, 6 D. Gaskell, J. Seely, R. Asaturyan, ∗ F. Benmokhtar, W. Boeglin, P. Bosted, M.H.S. Bukhari, M.E. Christy, S. Connell, † M.M. Dalton, 8 D. Day, J. Dunne, D. Dutta, 15 L. El Fassi, R. Ent, H. Fenker, H. Gao, 15 R.J. Holt, T. Horn, 8, 16 E. Hungerford, M.K. Jones, J. Jourdan, N. Kalantarians, C.E. Keppel, 13 D. Kiselev, ‡ A.F. Lung, S. Malace, D.G. Meekins, T. Mertens, H. Mkrtchyan, G. Niculescu, I. Niculescu, D.H. Potterveld, C. Perdrisat, V. Punjabi, X. Qian, P.E. Reimer, J. Roche, V.M. Rodriguez, O. Rondon, E. Schulte, K. Slifer, G.R. Smith, P. Solvignon, ∗ V. Tadevosyan, L. Tang, 13 G. Testa, R. Trojer, V. Tvaskis, F.R. Wesselmann, S.A. Wood, L. Yuan, and X. Zheng 6 Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA Argonne National Laboratory, Lemont, Illinois 60439, USA University of Massachusetts, Amherst, Massachusetts 01003, USA University of Tennessee, Knoxville, Tennessee 37966, USA University of Houston, Houston, Texas 77044, USA University of Virginia, Charlottesville, Virginia 22904, USA Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA Thomas Jefferson National Accelerator Facility, Newport News, Virginia 23606, USA Laboratory for Nuclear Science, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA A.I. Alikhanyan National Science Laboratory (Yerevan Physics Institute), 02 Alikhanyan Brothers Str., Yerevan 0036, Armenia University of Maryland, College Park, Maryland 20742, USA Florida International University, Miami, Florida 33199, USA Hampton University, Hampton, Virginia 23669, USA Mississippi State University, Mississippi State, Mississippi 39762, USA Triangle Universities Nuclear Laboratory, Duke University, Durham, North Carolina 27710, USA Catholic University of America, Washington, DC 20064, USA Basel University, Basel, Switzerland James Madison University, Harrisonburg, Virginia 22807, USA College of William and Mary, Wiliamsburg, Virginia, 23185, USA Norfolk State University, Norfolk, Virginia 23529, USA (Dated: October 19, 2021)

Short-range correlations (SRCs) have been identified as being responsible for the high-momentum tail of the nucleon momentum distribution, n(k). Hard, short-range interactions of nucleon pairs generate the high-momentum tail and imprint a universal character on n(k) for all nuclei at large momentum. Triple coincidence experiments have shown a strong dominance of np pairs, but these measurements involve large final-state interactions. This paper presents the results from Jefferson Lab experiment E08014 which measured inclusive electron scattering cross section from Ca isotopes. By comparing the inclusive cross section from Ca-48 to Ca-40 in a kinematic region dominated by SRCs we provide a new way to study the isospin structure of SRCs.

The ratio of the electric and magnetic form factor of the proton, $\mu_p G_E^p/G_M^p$, has been measured for elastic electron-proton scattering with polarized beam and target up to four-momentum transfer squared, $Q^2=5.66$ (GeV/c)$^2$ using the double spin asymmetry for target spin orientation aligned nearly perpendicular to the beam momentum direction. This measurement of $\mu_p G_E^p/G_M^p$ agrees with the $Q^2$ dependence of previous recoil polarization data and reconfirms the discrepancy at high $Q^2$ between the Rosenbluth and the polarization-transfer method with a different measurement technique and systematic uncertainties uncorrelated to those of the recoil-polarization measurements. The form factor ratio at $Q^2$=2.06 (GeV/c)$^2$ has been measured as $\mu_p G_E^p/G_M^p = 0.720 \pm 0.176_{stat} \pm 0.039_{sys}$, which is in agreement with an earlier measurement with the polarized target technique at similar kinematics. The form factor ratio at $Q^2$=5.66 (GeV/c)$^2$ has been determined as $\mu_p G_E^p/G_M^p=0.244\pm0.353_{stat}\pm0.013_{sys}$, which represents the highest $Q^2$ reach with the double spin asymmetry with polarized target to date.

The CLAS12 Forward Detector includes six independent lead-scintillator electromagnetic sampling calorimeters to provide the primary electron trigger and extend the CLAS12 detection capability to photons and neutrons. Each calorimeter package consists of two modules, the legacy Electromagnetic Calorimeter (EC) previously used in the CLAS detector, and a new pre-shower calorimeter (PCAL) located in front of the EC to extend the total detector radiation length, in order to fully absorb the electromagnetic showers induced by electrons with energies up to 12 GeV. Both calorimeters use a novel triangular hodoscope geometry with stereo readout. The PCAL uses an upgraded design to provide the high spatial resolution necessary for reconstructing pi(0) and eta decays, and neutrons with high efficiency. This paper treats the design, construction, and calibration of the PCAL and the preliminary combined performance of both detectors.

The Spin Asymmetries of the Nucleon Experiment measured two double spin asymmetries using a polarized proton target and polarized electron beam at two beam energies, 4.7 and 5.9 GeV. A large-acceptance open-configuration detector package identified scattered electrons at 40° and covered a wide range in Bjorken x (0.3<x<0.8). Proportional to an average color Lorentz force, the twist-3 matrix element, d[over ˜]_{2}^{p}, was extracted from the measured asymmetries at Q^{2} values ranging from 2.0 to 6.0  GeV^{2}. The data display the opposite sign compared to most quark models, including the lattice QCD result, and an unexpected scale dependence. Furthermore, when combined with the neutron data in the same Q^{2} range the results suggest a flavor independent average color Lorentz force.

S. Iqbal,1 F. Benmokhtar,2, ∗ M. Ivanov,3 N. See,1 K. Aniol,1, † D. W. Higinbotham,4 C. Boyd,2 S. Gilad,5 A. 2 Saha,4, ‡ J.M. Udias,6 J. S. Goodwill,2 D. Finton,2 Z. Ye,7 P. Solvignon,4, ‡ P. Aguilera,8 Z. Ahmed,9 3 H. Albataineh,10 K. Allada,4 B. Anderson,11 D. Anez,12 J. Annand,13 J. Arrington,7 T. Averett,14 H. 4 Baghdasaryan,15 X. Bai,16 A. Beck,17 S. Beck,17 V. Bellini,18 A. Camsonne,4 C. Chen,19 J.-P. Chen,4 K. 5 Chirapatpimol,15 E. Cisbani,20 M. M. Dalton,15, 4 A. Daniel,21 D. Day,15 W. Deconinck,5 M. Defurne,22 D. 6 Flay,23 N. Fomin,24 M. Friend,25 S. Frullani,20 E. Fuchey,23 F. Garibaldi,20 D. Gaskell,4 R. Gilman,26 S. 7 Glamazdin,27 C. Gu,15 P. Guèye,19 C. Hanretty,15 J.-O. Hansen,4 M. Hashemi Shabestari,15 O. Hen,28 M. 8 Huang,29 G. Jin,15 N. Kalantarians,15 H. Kang,30 A. Kelleher,5 I. Korover,28 J. LeRose,4 J. Leckey,31 R. 9 Lindgren,15 E. Long,11 J. Mammei,32 D. J. Margaziotis,1 P. Markowitz,33 D. Meekins,4 Z. Meziani,23 R. 10 Michaels,4 M. Mihovilovic,34 N. Muangma,5 C. Munoz Camacho,35 B. Norum,15 Nuruzzaman,36 11 K. Pan,5 S. Phillips,37 E. Piasetzky,28 I. Pomerantz,28 M. Posik,23 V. Punjabi,38 X. Qian,29 Y. 12 Qiang,4 X. Qiu,39 P. E. Reimer,7 A. Rakhman,9 S. Riordan,15, 40 G. Ron,41 O. Rondon-Aramayo,15, 4 13 L. Selvy,11 A. Shahinyan,42 R. Shneor,28 S. Sirca,43, 34 K. Slifer,37 N. Sparveris,23 R. Subedi,15 14 V. Sulkosky,5 D. Wang,15 J. W. Watson,11 L. B. Weinstein,10 B. Wojtsekhowski,4 S. A. Wood,4 15 I. Yaron,28 X. Zhan,7 J. Zhang,4 Y. W. Zhang,26 B. Zhao,14 X. Zheng,15 P. Zhu,44 and R. Zielinski37 16

We present extractions of the nucleon nonsinglet moments utilizing new precision data on the deuteron F_{2} structure function at large Bjorken-x determined via the Rosenbluth separation technique at Jefferson Lab Experimental Hall C. These new data are combined with a complementary set of data on the proton previously measured in Hall C at similar kinematics and world datasets on the proton and deuteron at lower x measured at SLAC and CERN. The new Jefferson Lab data provide coverage of the upper third of the x range, crucial for precision determination of the higher moments. In contrast to previous extractions, these moments have been corrected for nuclear effects in the deuteron using a new global fit to the deuteron and proton data. The obtained experimental moments represent an order of magnitude improvement in precision over previous extractions using high x data. Moreover, recent exciting developments in lattice QCD calculations provide a first ever comparison of these new experimental results with calculations of moments carried out at the physical pion mass, as well as a new approach that first calculates the quark distributions directly before determining moments.

This Article is brought to you for free and open access by the Physics at ODU Digital Commons. It has been accepted for inclusion in Physics Faculty Publications by an authorized administrator of ODU Digital Commons. For more information, please contact digitalcommons@odu.edu. Repository Citation CLAS Collaboration; Amaryan, M. J.; Careccia, S. L.; Dodge, G. E.; Hyde, C. E.; Kuhn, S. E.; Mayer, M.; Nepali, C. S.; Niroula, M. R.; Seraydaryan, H.; Tkachenko, S.; Weinstein, L.B.; and Zhang, J., "Photodisintegration of 4HE into p+t" (2009). Physics Faculty Publications. 353. https://digitalcommons.odu.edu/physics_fac_pubs/353

Received 18 May 2018DOI:https://doi.org/10.1103/PhysRevC.98.019907©2018 American Physical SocietyPhysics Subject Headings (PhySH)Research AreasCharge distributionsForm factorsNuclear charge distributionParticle interactionsParticles & FieldsNuclear Physics

The GEp-III and GEp-2 gamma experiments, carried out in Jefferson Lab's Hall C from 2007-2008, consisted of measurements of polarization transfer in elastic electron-proton scattering at momentum transfers of Q(2) = 2.5, 5.2, 6.8, and 8.54 GeV (2). These measurements were carried out to improve knowledge of the proton electromagnetic form factor ratio R = mu(P)G(E)(P)/G(M)(P) at large values of Q(2) and to search for effects beyond the Born approximation in polarization transfer observables at Q(2) = 2.5 GeV2. The final results of both experiments were reported in a recent archival publication. A full reanalysis of the data from both experiments was carried out in order to reduce the systematic and, for the GEp-2 gamma experiment, statistical uncertainties. This technical note provides additional details of the final analysis omitted from the main publication, including the final evaluation of the systematic uncertainties.

Subsequent to the release of our original paper, we discovered in the context of preparing our technical supplement [1] for journal publication that a typographical error had existed in the text file that the analysis program used to construct the beam polarization for both the original analysis, published in Ref. [2], and our final analysis. The electron-beam polarization P e and the analyzing power A y cancel exactly in the ratio R , which is proportional to the ratio P t / P l of the transferred polarization components. On the other hand, the extraction of the relative e dependence of P l / P Born l relies on knowledge of the beam polarization. As such, data taking was interrupted roughly every two days during the GEp - 2 ? experiment to perform invasive measurements of the beam polarization using the Hall C Moller polarimeter [3]. The run range affected by the typographical error was entirely contained within the data collected at Q 2 = 2.5 GeV 2 with a beam energy of E e = 3.680 GeV during January 2008. The data from this configuration were combined with the data collected at E e = 3.548 GeV due to the nearly complete overlap of these two settings in terms of Q 2 and e acceptance. It is worth remarking that this typographical error went unnoticed for so long because it only affected a small fraction of the data (less than half of the combined data for ? e ? = 0.790 ) and the difference between the actually assigned beam polarization and the polarization that should have been assigned was comparable in magnitude to the point-to-point systematic uncertainty of the measurement itself. As such, its effect did not show up in various diagnostic plots and statistical tests, such as the time stability of the extracted P l / P Born l ratio. The data for both E e = 3.548 and E e = 3.680 GeV were reprocessed using the corrected beam polarizations to determine the effect of the typographical error on the combined physics results at ? e ? = 0.790 . Because the value of P e cancels in the ratio R , changes in the assumed beam polarization can only affect the results for R via statistical fluctuations due to changes in the relative weighting of different run ranges in the unbinned maximum-likelihood estimators for R . These effects are negligible on the scale of both the statistical and the systematic uncertainties of the data. More noticeable changes are expected in the ratio P l / P Born l since the extracted value of P l is inversely proportional to the assumed value of P e . Table I shows the effect of the corrected beam polarization database on the polarization transfer observables for the combined data for the ? e ? = 0.790 setting, the only measurement affected by the typographical error. The analyzing power did not need to be recalibrated since it was determined using the ? e ? = 0.153 data, which were not affected by the typographical error. As expected, the change in the ratio R is negligible. The value of P Born l , which is computed event by event from the global fit described in the Appendix of the original paper and does not depend on P e , is also unchanged. The magnitudes of P t , P l , and P l / P Born l are reduced by a common multiplicative factor, reflecting the fact that the beam polarization had been underestimated for the run range affected by the typographical error. The most important result of the corrected analysis is that the ratio P l / P Born l has decreased by 0.0024 from 1.0167 to 1.0143, a change comparable in magnitude to the statistical uncertainty but small compared to the total and point-to-point systematic uncertainties. The P l / P Born l result for the original publication [2] would be reduced by the same multiplicative factor as the final result. The physics conclusions of both publications are not materially changed by this correction. (Table Presented). (Figure Presented).

We propose an evolution of the Mu2e experiment, called Mu2e-II, that would leverage advances in detector technology and utilize the increased proton intensity provided by the Fermilab PIP-II upgrade to improve the sensitivity for neutrinoless muon-to-electron conversion by one order of magnitude beyond the Mu2e experiment, providing the deepest probe of charged lepton flavor violation in the foreseeable future. Mu2e-II will use as much of the Mu2e infrastructure as possible, providing, where required, improvements to the Mu2e apparatus to accommodate the increased beam intensity and cope with the accompanying increase in backgrounds.

The Spin Asymmetries of the Nucleon Experiment ( SANE) performed inclusive, double-polarized electron scattering measurements of the proton at the Continuous Electron Beam Accelerator Facility at Jefferson Lab. A novel detector array observed scattered electrons of four-momentum transfer 2.5 < Q(2) < 6.5 GeV2 and Bjorken scaling 0.3 < x < 0.8 from initial beam energies of 4.7 and 5.9 GeV. Employing a polarized proton target whose magnetic field direction could be rotated with respect to the incident electron beam, both parallel and near perpendicular spin asymmetries were measured, allowing model-independent access to transverse polarization observables A(1), A(2), g(1,) g(2) and moment d(2) of the proton. This document summarizes the operation and performance of the polarized target, polarized electron beam, and novel detector systems used during the course of the experiment, and describes analysis techniques utilized to access the physics observables of interest. (c) 2017 Elsevier B.V. All rights reserved.