R. J. Holt - The Jefferson Lab Fpi Collaboration

R. J. Holt
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R. J. Holt
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The Jefferson Lab Fpi Collaboration
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Nuclear Experiment (40)
 
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Publications Authored By R. J. Holt

2016Aug
Authors: Jim Alexander, Marco Battaglieri, Bertrand Echenard, Rouven Essig, Matthew Graham, Eder Izaguirre, John Jaros, Gordan Krnjaic, Jeremy Mardon, David Morrissey, Tim Nelson, Maxim Perelstein, Matt Pyle, Adam Ritz, Philip Schuster, Brian Shuve, Natalia Toro, Richard G Van De Water, Daniel Akerib, Haipeng An, Konrad Aniol, Isaac J. Arnquist, David M. Asner, Henning O. Back, Keith Baker, Nathan Baltzell, Dipanwita Banerjee, Brian Batell, Daniel Bauer, James Beacham, Jay Benesch, James Bjorken, Nikita Blinov, Celine Boehm, Mariangela Bondí, Walter Bonivento, Fabio Bossi, Stanley J. Brodsky, Ran Budnik, Stephen Bueltmann, Masroor H. Bukhari, Raymond Bunker, Massimo Carpinelli, Concetta Cartaro, David Cassel, Gianluca Cavoto, Andrea Celentano, Animesh Chaterjee, Saptarshi Chaudhuri, Gabriele Chiodini, Hsiao-Mei Sherry Cho, Eric D. Church, D. A. Cooke, Jodi Cooley, Robert Cooper, Ross Corliss, Paolo Crivelli, Francesca Curciarello, Annalisa D'Angelo, Hooman Davoudiasl, Marzio De Napoli, Raffaella De Vita, Achim Denig, Patrick deNiverville, Abhay Deshpande, Ranjan Dharmapalan, Bogdan Dobrescu, Sergey Donskov, Raphael Dupre, Juan Estrada, Stuart Fegan, Torben Ferber, Clive Field, Enectali Figueroa-Feliciano, Alessandra Filippi, Bartosz Fornal, Arne Freyberger, Alexander Friedland, Iftach Galon, Susan Gardner, Francois-Xavier Girod, Sergei Gninenko, Andrey Golutvin, Stefania Gori, Christoph Grab, Enrico Graziani, Keith Griffioen, Andrew Haas, Keisuke Harigaya, Christopher Hearty, Scott Hertel, JoAnne Hewett, Andrew Hime, David Hitlin, Yonit Hochberg, Roy J. Holt, Maurik Holtrop, Eric W. Hoppe, Todd W. Hossbach, Lauren Hsu, Phil Ilten, Joe Incandela, Gianluca Inguglia, Kent Irwin, Igal Jaegle, Robert P. Johnson, Yonatan Kahn, Grzegorz Kalicy, Zhong-Bo Kang, Vardan Khachatryan, Venelin Kozhuharov, N. V. Krasnikov, Valery Kubarovsky, Eric Kuflik, Noah Kurinsky, Ranjan Laha, Gaia Lanfranchi, Dale Li, Tongyan Lin, Mariangela Lisanti, Kun Liu, Ming Liu, Ben Loer, Dinesh Loomba, Valery E. Lyubovitskij, Aaron Manalaysay, Giuseppe Mandaglio, Jeremiah Mans, W. J. Marciano, Thomas Markiewicz, Luca Marsicano, Takashi Maruyama, Victor A. Matveev, David McKeen, Bryan McKinnon, Dan McKinsey, Harald Merkel, Jeremy Mock, Maria Elena Monzani, Omar Moreno, Corina Nantais, Sebouh Paul, Michael Peskin, Vladimir Poliakov, Antonio D Polosa, Maxim Pospelov, Igor Rachek, Balint Radics, Mauro Raggi, Nunzio Randazzo, Blair Ratcliff, Alessandro Rizzo, Thomas Rizzo, Alan Robinson, Andre Rubbia, David Rubin, Dylan Rueter, Tarek Saab, Elena Santopinto, Richard Schnee, Jessie Shelton, Gabriele Simi, Ani Simonyan, Valeria Sipala, Oren Slone, Elton Smith, Daniel Snowden-Ifft, Matthew Solt, Peter Sorensen, Yotam Soreq, Stefania Spagnolo, James Spencer, Stepan Stepanyan, Jan Strube, Michael Sullivan, Arun S. Tadepalli, Tim Tait, Mauro Taiuti, Philip Tanedo, Rex Tayloe, Jesse Thaler, Nhan V. Tran, Sean Tulin, Christopher G. Tully, Sho Uemura, Maurizio Ungaro, Paolo Valente, Holly Vance, Jerry Vavra, Tomer Volansky, Belina von Krosigk, Andrew Whitbeck, Mike Williams, Peter Wittich, Bogdan Wojtsekhowski, Wei Xue, Jong Min Yoon, Hai-Bo Yu, Jaehoon Yu, Tien-Tien Yu, Yue Zhang, Yue Zhao, Yiming Zhong, Kathryn Zurek

This report, based on the Dark Sectors workshop at SLAC in April 2016, summarizes the scientific importance of searches for dark sector dark matter and forces at masses beneath the weak-scale, the status of this broad international field, the important milestones motivating future exploration, and promising experimental opportunities to reach these milestones over the next 5-10 years. Read More

Background: Octupole-deformed nuclei, such as that of $^{225}$Ra, are expected to amplify observable atomic electric dipole moments (EDMs) that arise from time-reversal and parity-violating interactions in the nuclear medium. In 2015, we reported the first "proof-of-principle" measurement of the $^{225}$Ra atomic EDM. Purpose: This work reports on the first of several experimental upgrades to improve the statistical sensitivity of our $^{225}$Ra EDM measurements by orders of magnitude and evaluates systematic effects that contribute to current and future levels of experimental sensitivity. Read More

Structure functions, as measured in lepton-nucleon scattering, have proven to be very useful in studying the quark dynamics within the nucleon. However, it is experimentally difficult to separately determine the longitudinal and transverse structure functions, and consequently there are substantially less data available for the longitudinal structure function in particular. Here we present separated structure functions for hydrogen and deuterium at low four--momentum transfer squared, Q^2< 1 GeV^2, and compare these with parton distribution parameterizations and a k_T factorization approach. Read More

An intense, 120 GeV proton beam incident on an extremely long, iron target generates enormous numbers of light-mass particles that also decay within that target. If one of these particles decays to a final state with a hidden gauge boson, or if such a particle is produced as a result of the initial collision, then that weakly interacting, hidden-sector particle may traverse the remainder of the target and be detected downstream through its possible decay to an $e^+e^-$, $\mu^+\mu^-$, or $\pi^+\pi^-$ final state. These conditions can be realized through an extension of the SeaQuest experiment at Fermilab, and in this initial investigation we consider how it can serve as an ultrasensitive probe of hidden vector gauge forces, both Abelian and non-Abelian. Read More

The radioactive radium-225 ($^{225}$Ra) atom is a favorable case to search for a permanent electric dipole moment (EDM). Due to its strong nuclear octupole deformation and large atomic mass, $^{225}$Ra is particularly sensitive to interactions in the nuclear medium that violate both time-reversal symmetry and parity. We have developed a cold-atom technique to study the spin precession of $^{225}$Ra atoms held in an optical dipole trap, and demonstrated the principle of this method by completing the first measurement of its atomic EDM, reaching an upper limit of $|$$d$($^{225}$Ra)$|$ $<$ $5. Read More

A bubble chamber has been developed to be used as an active target system for low energy nuclear astrophysics experiments. Adopting ideas from dark matter detection with superheated liquids, a detector system compatible with gamma-ray beams has been developed. This detector alleviates some of the limitations encountered in standard measurements of the minute cross sections of interest to stellar environments. Read More

Background: Measurements of forward exclusive meson production at different squared four-momenta of the exchanged virtual photon, $Q^2$, and at different four-momentum transfer, t, can be used to probe QCD's transition from meson-nucleon degrees of freedom at long distances to quark-gluon degrees of freedom at short scales. Ratios of separated response functions in $\pi^-$ and $\pi^+$ electroproduction are particularly informative. The ratio for transverse photons may allow this transition to be more easily observed, while the ratio for longitudinal photons provides a crucial verification of the assumed pole dominance, needed for reliable extraction of the pion form factor from electroproduction data. Read More

The ratio of the elastic $e^+ p$ to $e^- p$ scattering cross sections has been measured precisely, allowing the determination of the two-photon exchange contribution to these processes. This neglected contribution is believed to be the cause of the discrepancy between the Rosenbluth and polarization transfer methods of measuring the proton electromagnetic form factors. The experiment was performed at the VEPP-3 storage ring at beam energies of 1. Read More

The parity-violating asymmetries between a longitudinally-polarized electron beam and an unpolarized deuterium target have been measured recently. The measurement covered two kinematic points in the deep inelastic scattering region and five in the nucleon resonance region. We provide here details of the experimental setup, data analysis, and results on all asymmetry measurements including parity-violating electron asymmetries and those of inclusive pion production and beam-normal asymmetries. Read More

2014Apr
Affiliations: 1The Jefferson Lab Fpi Collaboration, 2The Jefferson Lab Fpi Collaboration, 3The Jefferson Lab Fpi Collaboration, 4The Jefferson Lab Fpi Collaboration, 5The Jefferson Lab Fpi Collaboration, 6The Jefferson Lab Fpi Collaboration, 7The Jefferson Lab Fpi Collaboration, 8The Jefferson Lab Fpi Collaboration, 9The Jefferson Lab Fpi Collaboration, 10The Jefferson Lab Fpi Collaboration, 11The Jefferson Lab Fpi Collaboration, 12The Jefferson Lab Fpi Collaboration, 13The Jefferson Lab Fpi Collaboration, 14The Jefferson Lab Fpi Collaboration, 15The Jefferson Lab Fpi Collaboration, 16The Jefferson Lab Fpi Collaboration, 17The Jefferson Lab Fpi Collaboration, 18The Jefferson Lab Fpi Collaboration, 19The Jefferson Lab Fpi Collaboration, 20The Jefferson Lab Fpi Collaboration, 21The Jefferson Lab Fpi Collaboration, 22The Jefferson Lab Fpi Collaboration, 23The Jefferson Lab Fpi Collaboration, 24The Jefferson Lab Fpi Collaboration, 25The Jefferson Lab Fpi Collaboration, 26The Jefferson Lab Fpi Collaboration, 27The Jefferson Lab Fpi Collaboration, 28The Jefferson Lab Fpi Collaboration, 29The Jefferson Lab Fpi Collaboration, 30The Jefferson Lab Fpi Collaboration, 31The Jefferson Lab Fpi Collaboration, 32The Jefferson Lab Fpi Collaboration, 33The Jefferson Lab Fpi Collaboration, 34The Jefferson Lab Fpi Collaboration, 35The Jefferson Lab Fpi Collaboration, 36The Jefferson Lab Fpi Collaboration, 37The Jefferson Lab Fpi Collaboration, 38The Jefferson Lab Fpi Collaboration, 39The Jefferson Lab Fpi Collaboration, 40The Jefferson Lab Fpi Collaboration, 41The Jefferson Lab Fpi Collaboration, 42The Jefferson Lab Fpi Collaboration, 43The Jefferson Lab Fpi Collaboration, 44The Jefferson Lab Fpi Collaboration, 45The Jefferson Lab Fpi Collaboration, 46The Jefferson Lab Fpi Collaboration, 47The Jefferson Lab Fpi Collaboration, 48The Jefferson Lab Fpi Collaboration, 49The Jefferson Lab Fpi Collaboration, 50The Jefferson Lab Fpi Collaboration, 51The Jefferson Lab Fpi Collaboration, 52The Jefferson Lab Fpi Collaboration, 53The Jefferson Lab Fpi Collaboration, 54The Jefferson Lab Fpi Collaboration, 55The Jefferson Lab Fpi Collaboration, 56The Jefferson Lab Fpi Collaboration, 57The Jefferson Lab Fpi Collaboration, 58The Jefferson Lab Fpi Collaboration, 59The Jefferson Lab Fpi Collaboration, 60The Jefferson Lab Fpi Collaboration, 61The Jefferson Lab Fpi Collaboration, 62The Jefferson Lab Fpi Collaboration, 63The Jefferson Lab Fpi Collaboration, 64The Jefferson Lab Fpi Collaboration, 65The Jefferson Lab Fpi Collaboration, 66The Jefferson Lab Fpi Collaboration, 67The Jefferson Lab Fpi Collaboration, 68The Jefferson Lab Fpi Collaboration, 69The Jefferson Lab Fpi Collaboration, 70The Jefferson Lab Fpi Collaboration, 71The Jefferson Lab Fpi Collaboration, 72The Jefferson Lab Fpi Collaboration, 73The Jefferson Lab Fpi Collaboration, 74The Jefferson Lab Fpi Collaboration, 75The Jefferson Lab Fpi Collaboration, 76The Jefferson Lab Fpi Collaboration, 77The Jefferson Lab Fpi Collaboration, 78The Jefferson Lab Fpi Collaboration, 79The Jefferson Lab Fpi Collaboration, 80The Jefferson Lab Fpi Collaboration, 81The Jefferson Lab Fpi Collaboration, 82The Jefferson Lab Fpi Collaboration, 83The Jefferson Lab Fpi Collaboration, 84The Jefferson Lab Fpi Collaboration, 85The Jefferson Lab Fpi Collaboration, 86The Jefferson Lab Fpi Collaboration, 87The Jefferson Lab Fpi Collaboration, 88The Jefferson Lab Fpi Collaboration

The study of exclusive $\pi^{\pm}$ electroproduction on the nucleon, including separation of the various structure functions, is of interest for a number of reasons. The ratio $R_L=\sigma_L^{\pi^-}/\sigma_L^{\pi^+}$ is sensitive to isoscalar contamination to the dominant isovector pion exchange amplitude, which is the basis for the determination of the charged pion form factor from electroproduction data. A change in the value of $R_T=\sigma_T^{\pi^-}/\sigma_T^{\pi^+}$ from unity at small $-t$, to 1/4 at large $-t$, would suggest a transition from coupling to a (virtual) pion to coupling to individual quarks. Read More

The valence region is exceedingly important in hadron physics since this region not only defines a hadron but also is an excellent discriminator of nucleon structure models. Present uncertainties in light quark distribution functions at high x could also impact high energy physics. Here we will describe a new generation of experiments at Jefferson Lab that is aimed at the high x region of the nucleon. Read More

Dyson-Schwinger equation treatments of the strong interaction show that the presence and importance of nonpointlike diquark correlations within the nucleon are a natural consequence of dynamical chiral symmetry breaking. Using this foundation, we deduce a collection of simple formulae, expressed in terms of diquark appearance and mixing probabilities, from which one may compute ratios of longitudinal-spin-dependent u- and d-quark parton distribution functions on the domain x =1. A comparison with predictions from other approaches plus a consideration of extant and planned experiments shows that the measurement of nucleon longitudinal spin asymmetries on x =1 can add considerably to our capacity for discriminating between contemporary pictures of nucleon structure. Read More

Gas targets are often used at accelerator facilities. A design of high-pressure gas cells that are suitable for hydrogen and helium isotopes at relatively high electron beam currents is presented. In particular, we consider rare gas targets, $^3$H$_2$ and $^3$He. Read More

We demonstrate a technique for transferring $^{226}$Ra atoms from a 3-dimensional magneto-optical-trap (MOT) into a standing wave optical dipole trap (ODT) in an adjacent chamber. The resulting small trapping volume (120 $\mu$m in diameter) allows for high control of the electric and magnetic fields applied to the atoms. The atoms are first transferred to a traveling-wave optical dipole trap, which is then translated 46 cm to a science chamber. Read More

We report on parity-violating asymmetries in the nucleon resonance region measured using $5 - 6$ GeV longitudinally polarized electrons scattering off an unpolarized deuterium target. These results are the first parity-violating asymmetry data in the resonance region beyond the $\Delta(1232)$, and provide a verification of quark-hadron duality in the nucleon electroweak $\gamma Z$ interference structure functions at the (10-15)% level. The results are of particular interest to models relevant for calculating the $\gamma Z$ box-diagram corrections to elastic parity-violating electron scattering measurements. Read More

The Proton Radius Puzzle is the inconsistency between the proton radius determined from muonic hydrogen and the proton radius determined from atomic hydrogen level transitions and ep elastic scattering. No generally accepted resolution to the Puzzle has been found. Possible solutions generally fall into one of three categories: the two radii are different due to novel beyond-standard-model physics, the two radii are different due to novel aspects of nucleon structure, and the two radii are the same, but there are underestimated uncertainties or other issues in the ep experiments. Read More

We have devised a technique for measuring some of the most important nuclear reactions in stars which we expect to provide considerable improvement over previous experiments. Adapting ideas from dark matter search experiments with bubble chambers, we have found that a superheated liquid is sensitive to recoils produced from \gamma-rays photodisintegrating the nuclei of the liquid. The main advantage of the new target-detector system is a gain in yield of six orders of magnitude over conventional gas targets due to the higher mass density of liquids. Read More

This White Paper presents the science case of an Electron-Ion Collider (EIC), focused on the structure and interactions of gluon-dominated matter, with the intent to articulate it to the broader nuclear science community. It was commissioned by the managements of Brookhaven National Laboratory (BNL) and Thomas Jefferson National Accelerator Facility (JLab) with the objective of presenting a summary of scientific opportunities and goals of the EIC as a follow-up to the 2007 NSAC Long Range plan. This document is a culmination of a community-wide effort in nuclear science following a series of workshops on EIC physics and, in particular, the focused ten-week program on "Gluons and quark sea at high energies" at the Institute for Nuclear Theory in Fall 2010. Read More

We provide a perspective on studies aimed at observing the transition between hadronic and quark-gluonic descriptions of reactions involving light nuclei. We begin by summarizing the results for relatively simple reactions such as the pion form factor and the neutral pion transition form factor as well as that for the nucleon and end with exclusive photoreactions in our simplest nuclei. A particular focus will be on reactions involving the deuteron. Read More

2012May
Authors: J. L. Hewett, H. Weerts, R. Brock, J. N. Butler, B. C. K. Casey, J. Collar, A. de Gouvea, R. Essig, Y. Grossman, W. Haxton, J. A. Jaros, C. K. Jung, Z. T. Lu, K. Pitts, Z. Ligeti, J. R. Patterson, M. Ramsey-Musolf, J. L. Ritchie, A. Roodman, K. Scholberg, C. E. M. Wagner, G. P. Zeller, S. Aefsky, A. Afanasev, K. Agashe, C. Albright, J. Alonso, C. Ankenbrandt, M. Aoki, C. A. Arguelles, N. Arkani-Hamed, J. R. Armendariz, C. Armendariz-Picon, E. Arrieta Diaz, J. Asaadi, D. M. Asner, K. S. Babu, K. Bailey, O. Baker, B. Balantekin, B. Baller, M. Bass, B. Batell, J. Beacham, J. Behr, N. Berger, M. Bergevin, E. Berman, R. Bernstein, A. J. Bevan, M. Bishai, M. Blanke, S. Blessing, A. Blondel, T. Blum, G. Bock, A. Bodek, G. Bonvicini, F. Bossi, J. Boyce, R. Breedon, M. Breidenbach, S. J. Brice, R. A. Briere, S. Brodsky, C. Bromberg, A. Bross, T. E. Browder, D. A. Bryman, M. Buckley, R. Burnstein, E. Caden, P. Campana, R. Carlini, G. Carosi, C. Castromonte, R. Cenci, I. Chakaberia, M. C. Chen, C. H. Cheng, B. Choudhary, N. H. Christ, E. Christensen, M. E. Christy, T. E. Chupp, E. Church, D. B. Cline, T. E. Coan, P. Coloma, J. Comfort, L. Coney, J. Cooper, R. J. Cooper, R. Cowan, D. F. Cowen, D. Cronin-Hennessy, A. Datta, G. S. Davies, M. Demarteau, D. P. DeMille, A. Denig, R. Dermisek, A. Deshpande, M. S. Dewey, R. Dharmapalan, J. Dhooghe, M. R. Dietrich, M. Diwan, Z. Djurcic, S. Dobbs, M. Duraisamy, B. Dutta, H. Duyang, D. A. Dwyer, M. Eads, B. Echenard, S. R. Elliott, C. Escobar, J. Fajans, S. Farooq, C. Faroughy, J. E. Fast, B. Feinberg, J. Felde, G. Feldman, P. Fierlinger, P. Fileviez Perez, B. Filippone, P. Fisher, B. T. Flemming, K. T. Flood, R. Forty, M. J. Frank, A. Freyberger, A. Friedland, R. Gandhi, K. S. Ganezer, A. Garcia, F. G. Garcia, S. Gardner, L. Garrison, A. Gasparian, S. Geer, V. M. Gehman, T. Gershon, M. Gilchriese, C. Ginsberg, I. Gogoladze, M. Gonderinger, M. Goodman, H. Gould, M. Graham, P. W. Graham, R. Gran, J. Grange, G. Gratta, J. P. Green, H. Greenlee, R. C. Group, E. Guardincerri, V. Gudkov, R. Guenette, A. Haas, A. Hahn, T. Han, T. Handler, J. C. Hardy, R. Harnik, D. A. Harris, F. A. Harris, P. G. Harris, J. Hartnett, B. He, B. R. Heckel, K. M. Heeger, S. Henderson, D. Hertzog, R. Hill, E. A Hinds, D. G. Hitlin, R. J. Holt, N. Holtkamp, G. Horton-Smith, P. Huber, W. Huelsnitz, J. Imber, I. Irastorza, J. Jaeckel, I. Jaegle, C. James, A. Jawahery, D. Jensen, C. P. Jessop, B. Jones, H. Jostlein, T. Junk, A. L. Kagan, M. Kalita, Y. Kamyshkov, D. M. Kaplan, G. Karagiorgi, A. Karle, T. Katori, B. Kayser, R. Kephart, S. Kettell, Y. K. Kim, M. Kirby, K. Kirch, J. Klein, J. Kneller, A. Kobach, M. Kohl, J. Kopp, M. Kordosky, W. Korsch, I. Kourbanis, A. D. Krisch, P. Krizan, A. S. Kronfeld, S. Kulkarni, K. S. Kumar, Y. Kuno, T. Kutter, T. Lachenmaier, M. Lamm, J. Lancaster, M. Lancaster, C. Lane, K. Lang, P. Langacker, S. Lazarevic, T. Le, K. Lee, K. T. Lesko, Y. Li, M. Lindgren, A. Lindner, J. Link, D. Lissauer, L. S. Littenberg, B. Littlejohn, C. Y. Liu, W. Loinaz, W. Lorenzon, W. C. Louis, J. Lozier, L. Ludovici, L. Lueking, C. Lunardini, D. B. MacFarlane, P. A. N. Machado, P. B. Mackenzie, J. Maloney, W. J. Marciano, W. Marsh, M. Marshak, J. W. Martin, C. Mauger, K. S. McFarland, C. McGrew, G. McLaughlin, D. McKeen, R. McKeown, B. T. Meadows, R. Mehdiyev, D. Melconian, H. Merkel, M. Messier, J. P. Miller, G. Mills, U. K. Minamisono, S. R. Mishra, I. Mocioiu, S. Moed Sher, R. N. Mohapatra, B. Monreal, C. D. Moore, J. G. Morfin, J. Mousseau, L. A. Moustakas, G. Mueller, P. Mueller, M. Muether, H. P. Mumm, C. Munger, H. Murayama, P. Nath, O. Naviliat-Cuncin, J. K. Nelson, D. Neuffer, J. S. Nico, A. Norman, D. Nygren, Y. Obayashi, T. P. O'Connor, Y. Okada, J. Olsen, L. Orozco, J. L. Orrell, J. Osta, B. Pahlka, J. Paley, V. Papadimitriou, M. Papucci, S. Parke, R. H. Parker, Z. Parsa, K. Partyka, A. Patch, J. C. Pati, R. B. Patterson, Z. Pavlovic, G. Paz, G. N. Perdue, D. Perevalov, G. Perez, R. Petti, W. Pettus, A. Piepke, M. Pivovaroff, R. Plunkett, C. C. Polly, M. Pospelov, R. Povey, A. Prakesh, M. V. Purohit, S. Raby, J. L. Raaf, R. Rajendran, S. Rajendran, G. Rameika, R. Ramsey, A. Rashed, B. N. Ratcliff, B. Rebel, J. Redondo, P. Reimer, D. Reitzner, F. Ringer, A. Ringwald, S. Riordan, B. L. Roberts, D. A. Roberts, R. Robertson, F. Robicheaux, M. Rominsky, R. Roser, J. L. Rosner, C. Rott, P. Rubin, N. Saito, M. Sanchez, S. Sarkar, H. Schellman, B. Schmidt, M. Schmitt, D. W. Schmitz, J. Schneps, A. Schopper, P. Schuster, A. J. Schwartz, M. Schwarz, J. Seeman, Y. K. Semertzidis, K. K. Seth, Q. Shafi, P. Shanahan, R. Sharma, S. R. Sharpe, M. Shiozawa, V. Shiltsev, K. Sigurdson, P. Sikivie, J. Singh, D. Sivers, T. Skwarnicki, N. Smith, J. Sobczyk, H. Sobel, M. Soderberg, Y. H. Song, A. Soni, P. Souder, A. Sousa, J. Spitz, M. Stancari, G. C. Stavenga, J. H. Steffen, S. Stepanyan, D. Stoeckinger, S. Stone, J. Strait, M. Strassler, I. A. Sulai, R. Sundrum, R. Svoboda, B. Szczerbinska, A. Szelc, T. Takeuchi, P. Tanedo, S. Taneja, J. Tang, D. B. Tanner, R. Tayloe, I. Taylor, J. Thomas, C. Thorn, X. Tian, B. G. Tice, M. Tobar, N. Tolich, N. Toro, I. S. Towner, Y. Tsai, R. Tschirhart, C. D. Tunnell, M. Tzanov, A. Upadhye, J. Urheim, S. Vahsen, A. Vainshtein, E. Valencia, R. G. Van de Water, R. S. Van de Water, M. Velasco, J. Vogel, P. Vogel, W. Vogelsang, Y. W. Wah, D. Walker, N. Weiner, A. Weltman, R. Wendell, W. Wester, M. Wetstein, C. White, L. Whitehead, J. Whitmore, E. Widmann, G. Wiedemann, J. Wilkerson, G. Wilkinson, P. Wilson, R. J. Wilson, W. Winter, M. B. Wise, J. Wodin, S. Wojcicki, B. Wojtsekhowski, T. Wongjirad, E. Worcester, J. Wurtele, T. Xin, J. Xu, T. Yamanaka, Y. Yamazaki, I. Yavin, J. Yeck, M. Yeh, M. Yokoyama, J. Yoo, A. Young, E. Zimmerman, K. Zioutas, M. Zisman, J. Zupan, R. Zwaska

The Proceedings of the 2011 workshop on Fundamental Physics at the Intensity Frontier. Science opportunities at the intensity frontier are identified and described in the areas of heavy quarks, charged leptons, neutrinos, proton decay, new light weakly-coupled particles, and nucleons, nuclei, and atoms. Read More

2012Jan
Authors: L. El Fassi, L. Zana, K. Hafidi, M. Holtrop, B. Mustapha, W. K. Brooks, H. Hakobyan, X. Zheng, K. P. Adhikari, D. Adikaram, M. Aghasyan, M. J. Amaryan, M. Anghinolfi, J. Arrington, H. Avakian, H. Baghdasaryan, M. Battaglieri, V. Batourine, I. Bedlinskiy, A. S. Biselli, C. Bookwalter, D. Branford, W. J. Briscoe, S. Bultmann, V. D. Burkert, D. S. Carman, A. Celentano, S. Chandavar, P. L. Cole, M. Contalbrigo, V. Crede, A. D'Angelo, A. Daniel, N. Dashyan, R. De Vita, E. De Sanctis, A. Deur, B. Dey, R. Dickson, C. Djalali, G. E. Dodge, D. Doughty, R. Dupre, H. Egiyan, A. El Alaoui, L. Elouadrhiri, P. Eugenio, G. Fedotov, S. Fegan, M. Y. Gabrielyan, M. Garcon, N. Gevorgyan, G. P. Gilfoyle, K. L. Giovanetti, F. X. Girod, J. T. Goetz, W. Gohn, E. Golovatch, R. W. Gothe, K. A. Griffioen, M. Guidal, L. Guo, C. Hanretty, D. Heddle, K. Hicks, R. J. Holt, C. E. Hyde, Y. Ilieva, D. G. Ireland, B. S. Ishkhanov, E. L. Isupov, S. S. Jawalkar, D. Keller, M. Khandaker, P. Khetarpal, A. Kim, W. Kim, A. Klein, F. J. Klein, V. Kubarovsky, S. E. Kuhn, S. V. Kuleshov, V. Kuznetsov, J. M. Laget, H. Y. Lu, I. J. D. MacGregor, Y. Mao, N. Markov, M. Mayer, J. McAndrew, B. McKinnon, C. A. Meyer, T. Mineeva, M. Mirazita, V. Mokeev, B. Moreno, H. Moutarde, E. Munevar, P. Nadel-Turonski, A. Ni, S. Niccolai, G. Niculescu, I. Niculescu, M. Osipenko, A. I. Ostrovidov, L. Pappalardo, R. Paremuzyan, K. Park, S. Park, E. Pasyuk, S. Anefalos Pereira, E. Phelps, S. Pisano, S. Pozdniakov, J. W. Price, S. Procureur, D. Protopopescu, B. A. Raue, P. E. Reimer, G. Ricco, D. Rimal, M. Ripani, B. G. Ritchie, G. Rosner, P. Rossi, F. Sabatie, M. S. Saini, C. Salgado, D. Schott, R. A. Schumacher, H. Seraydaryan, Y. G. Sharabian, E. S. Smith, G. D. Smith, D. I. Sober, D. Sokhan, S. S. Stepanyan, S. Stepanyan, P. Stoler, S. Strauch, M. Taiuti, W. Tang, C. E. Taylor, D. J. Tedeschi, S. Tkachenko, M. Ungaro, B . Vernarsky, M. F. Vineyard, H. Voskanyan, E. Voutier, D. Watts, L. B. Weinstein, D. P. Weygand, M. H. Wood, N. Zachariou, B. Zhao, Z. W. Zhao

We have measured the nuclear transparency of the incoherent diffractive $A(e,e'\rho^0)$ process in $^{12}$C and $^{56}$Fe targets relative to $^2$H using a 5 GeV electron beam. The nuclear transparency, the ratio of the produced $\rho^0$'s on a nucleus relative to deuterium, which is sensitive to $\rho A$ interaction, was studied as function of the coherence length ($l_c$), a lifetime of the hadronic fluctuation of the virtual photon, and the four-momentum transfer squared ($Q^2$). While the transparency for both $^{12}$C and $^{56}$Fe showed no $l_c$ dependence, a significant $Q^2$ dependence was measured, which is consistent with calculations that included the color transparency effects. Read More

We report on the status of the Novosibirsk experiment on a precision measurement of the ratio $R$ of the elastic $e^+ p$ and $e^- p$ scattering cross sections. Such measurements determine the two-photon exchange effect in elastic electron-proton scattering. The experiment is conducted at the VEPP-3 storage ring using a hydrogen internal gas target. Read More

A simple method to generate a two-dimensional binary grid pattern, which allows for absolute and accurate self-location in a finite planar region, is proposed. The pattern encodes position information in a local way so that reading a small number of its black or white pixels at any place provides sufficient data from which the location can be decoded both efficiently and robustly. Read More

A large set of cross sections for semi-inclusive electroproduction of charged pions ($\pi^\pm$) from both proton and deuteron targets was measured. The data are in the deep-inelastic scattering region with invariant mass squared $W^2$ > 4 GeV$^2$ and range in four-momentum transfer squared $2 < Q^2 < 4$ (GeV/c)$^2$, and cover a range in the Bjorken scaling variable 0.2 < x < 0. Read More

We present new data on electron scattering from a range of nuclei taken in Hall C at Jefferson Lab. For heavy nuclei, we observe a rapid falloff in the cross section for $x>1$, which is sensitive to short range contributions to the nuclear wave-function, and in deep inelastic scattering corresponds to probing extremely high momentum quarks. This result agrees with higher energy muon scattering measurements, but is in sharp contrast to neutrino scattering measurements which suggested a dramatic enhancement in the distribution of the `super-fast' quarks probed at x>1. Read More

We provide an experimental and theoretical perspective on the behavior of unpolarized distribution functions for the nucleon and pion on the valence-quark domain; namely, Bjorken-x \gtrsim 0.4. This domain is key to much of hadron physics; e. Read More

Cross sections for the reaction ${^1}$H($e,e'\pi^+$)$n$ were measured in Hall C at Thomas Jefferson National Accelerator Facility (JLab) using the CEBAF high-intensity, continous electron beam in order to determine the charged pion form factor. Data were taken for central four-momentum transfers ranging from $Q^2$=0.60 to 2. Read More

The charged pion form factor, Fpi(Q^2), is an important quantity which can be used to advance our knowledge of hadronic structure. However, the extraction of Fpi from data requires a model of the 1H(e,e'pi+)n reaction, and thus is inherently model dependent. Therefore, a detailed description of the extraction of the charged pion form factor from electroproduction data obtained recently at Jefferson Lab is presented, with particular focus given to the dominant uncertainties in this procedure. Read More

Neutron structure functions can be extracted from proton and deuteron data and a representation of the deuteron structure. This procedure does not require DIS approximations or quark structure assumptions. We find that the results depend critically on properly accounting for the Q^2 dependence of proton and deuteron data. Read More

This chapter of the report of the ``Flavour in the era of the LHC'' Workshop discusses the theoretical, phenomenological and experimental issues related to flavour phenomena in the charged lepton sector and in flavour-conserving CP-violating processes. We review the current experimental limits and the main theoretical models for the flavour structure of fundamental particles. We analyze the phenomenological consequences of the available data, setting constraints on explicit models beyond the Standard Model, presenting benchmarks for the discovery potential of forthcoming measurements both at the LHC and at low energy, and exploring options for possible future experiments. Read More

The root-mean-square (rms) nuclear charge radius of ^8He, the most neutron-rich of all particle-stable nuclei, has been determined for the first time to be 1.93(3) fm. In addition, the rms charge radius of ^6He was measured to be 2. Read More

We reconsider parity violation experiments in atomic hydrogen and deuterium in the light of existing tests of the Electroweak interactions, and assess whether new experiments, using improved experimental techniques, could make useful contributions to testing the Standard Model (SM). We find that, if parity experiments in hydrogen can be done, they remain highly desirable because there is negligible atomic-physics uncertainty and low energy tests of weak neutral current interactions are needed to probe for new physics beyond the SM. Of particular interest would be a measurement of the nuclear spin independent coupling C_{1D} for the deuteron at a combined error (theory + experiment) of 0. Read More

We have demonstrated Zeeman slowing and capture of neutral Ra-225 and Ra-226 atoms in a magneto-optical trap (MOT). The intercombination transition 1S0-3P1 is the only quasi-cycling transition in radium and was used for laser-cooling and trapping. Repumping along the 3D1-1P1 transition extended the lifetime of the trap from milliseconds to seconds. Read More

New accurate measurement of tensor analyzing powers T20, T21 and T22 in deuteron photodisintegration has been performed. Wide-aperture non-magnetic detectors allowed to cover broad kinematic ranges in a single setup: photon energy = 25 to 600 MeV, proton emission angle in CM = 24 to 48 deg. and 70 to 102 deg. Read More

The parton distribution function of the pion in the valence region is extracted in a next-to-leading order analysis from Fermilab E-615 pionic Drell-Yan data. The effects of the parameterization of the pion's valence distributions are examined. Modern nucleon parton distributions and nuclear corrections were used and possible effects from higher twist contributions were considered in the analysis. Read More

We report on a detailed study of longitudinal strength in the nucleon resonance region, presenting new results from inclusive electron-proton cross sections measured at Jefferson Lab Hall C in the four-momentum transfer range 0.2 < Q^2 < 5.5 GeV^2. Read More

It has been suggested that two-photon exchange corrections could explain the discrepancy between Rosenbluth extractions of the proton form factors and recent polarization transfer measurements. We propose a precise comparison of electron-proton and positron-proton scattering at Q^2=1.6 GeV^2 to determine if two-photon exchange at moderate Q^2 values is in fact able to explain the discrepancy. Read More

We have performed precision laser spectroscopy on individual 6He (t1/2 = 0.8 s) atoms confined and cooled in a magneto-optical trap, and measured the isotope shift between 6He and 4He to be 43,194.772 +/- 0. Read More

Our knowledge on the possible existence in nature of stable exotic particles depends solely upon experimental observation. Guided by this general principle and motivated by theoretical hypotheses on the existence of stable particles of strange quark matter, a variety of experimental searches have been performed. We provide an introduction to the theoretical hypotheses, an overview of the past searches, and a more detailed description of a recent search for helium-like strangelets in the Earth's atmosphere using a sensitive laser spectroscopy method. Read More

A sensitive laser spectroscopic method has been applied to the quantitative determination of the isotope ratio of helium at the level of 3He/4He = 10^-7 - 10^-5. The resonant absorption of 1083 nm laser light by the metastable 3He atoms in a discharge cell was measured with the frequency modulation saturation spectroscopy technique while the abundance of 4He was measured by a direct absorption technique. The results on three different samples extracted from the atmosphere and commercial helium gas were in good agreement with values obtained with mass spectrometry. Read More

Motivated by the theoretical hypotheses on the existence of heretofore unobserved stable elementary particles and exotic nuclear states, we searched for doubly-charged particles, as anomalously heavy isotopes of helium, in the Earth's atmoshpere using a sensitive laser spectroscopy technique. The concentration of noble-gas-like atoms in the atmosphere and the subsequent very large depletion of the light He-3,4 isotopes allow us to set stringent limits on th abundance: 10^-13 to 10^-17 per atom in the solar system, over the mass range of 20 to 10,000 amu. Read More