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Abstract
A neutron star was first detected as a pulsar in 1967. It is one of the most mysterious compact objects in the universe, with a radius of the order of 10 km and masses that can reach two solar masses. In fact, neutron stars are star remnants, a kind of stellar zombie (they die, but do not disappear). In the last decades, astronomical observations yielded various contraints for neutron star masses, and finally, in 2017, a gravitational wave was detected (GW170817). Its source was identified as the merger of two neutron stars coming from NGC 4993, a galaxy 140 million light years away from us. The very same event was detected in γ-ray, X-ray, UV, IR, radio frequency and even in the optical region of the electromagnetic spectrum, starting the new era of multi-messenger astronomy. To understand and describe neutron stars, an appropriate equation of state that satisfies bulk nuclear matter properties is necessary. GW170817 detection contributed with extra constraints to determine it. On the other hand, magnetars are the same sort of compact object, but bearing much stronger magnetic fields that can reach up to 1015 G on the surface as compared with the usual 1012 G present in ordinary pulsars. While the description of ordinary pulsars is not completely established, describing magnetars poses extra challenges. In this paper, I give an overview on the history of neutron stars and on the development of nuclear models and show how the description of the tiny world of the nuclear physics can help the understanding of the cosmos, especially of the neutron stars.
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2
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Hassan R, Haque MM, Haque A, Shorifuddoza M, Khandker MH, Patoary MAR, Basak AK, Maaza M, Saha BC, Uddin MA. Relativistic study on the scattering of electrons and positrons from atomic iron at energies 1 eV – 10 keV. Mol Phys 2020. [DOI: 10.1080/00268976.2020.1849838] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Affiliation(s)
- R. Hassan
- Department of Physics, University of Rajshahi, Rajshahi, Bangladesh
| | - M. M. Haque
- Department of Physics, University of Rajshahi, Rajshahi, Bangladesh
| | - A.K.F. Haque
- Department of Physics, University of Rajshahi, Rajshahi, Bangladesh
- Nanosciences African Network (NANOAFNET), iThemba LABS-National Research Foundation, Cape Town, South Africa
| | - M. Shorifuddoza
- Department of Physics, Pabna University of Science and Technology, Pabna, Bangladesh
| | | | | | - A. K. Basak
- Department of Physics, University of Rajshahi, Rajshahi, Bangladesh
| | - M. Maaza
- Nanosciences African Network (NANOAFNET), iThemba LABS-National Research Foundation, Cape Town, South Africa
| | - B. C. Saha
- Department of Physics, Florida A & M University, Tallahassee, FL, USA
| | - M. Alfaz Uddin
- Department of Physics, Pabna University of Science and Technology, Pabna, Bangladesh
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3
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Abstract
The Lagrangian that defines quantum chromodynamics (QCD), the strong interaction piece of the Standard Model, appears very simple. Nevertheless, it is responsible for an astonishing array of high-level phenomena with enormous apparent complexity, e.g., the existence, number and structure of atomic nuclei. The source of all these things can be traced to emergent mass, which might itself be QCD’s self-stabilising mechanism. A background to this perspective is provided, presenting, inter alia, a discussion of the gluon mass and QCD’s process-independent effective charge and highlighting an array of observable expressions of emergent mass, ranging from its manifestations in pion parton distributions to those in nucleon electromagnetic form factors.
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4
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Precision measurement of the weak charge of the proton. Nature 2018; 557:207-211. [DOI: 10.1038/s41586-018-0096-0] [Citation(s) in RCA: 92] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2017] [Accepted: 04/05/2018] [Indexed: 11/09/2022]
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5
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Androic D, Armstrong D, Asaturyan A, Averett T, Balewski J, Bartlett K, Beaufait J, Beminiwattha R, Benesch J, Benmokhtar F, Birchall J, Carlini R, Cates G, Cornejo J, Covrig S, Dalton M, Davis C, Deconinck W, Diefenbach J, Dowd J, Dunne J, Dutta D, Duvall W, Elaasar M, Falk W, Finn J, Forest T, Gal C, Gaskell D, Gericke M, Grames J, Gray V, Grimm K, Guo F, Hoskins J, Johnston K, Jones D, Jones M, Jones R, Kargiantoulakis M, King P, Korkmaz E, Kowalski S, Leacock J, Leckey J, Lee A, Lee J, Lee L, MacEwan S, Mack D, Magee J, Mahurin R, Mammei J, Martin J, McHugh M, Meekins D, Mei J, Michaels R, Micherdzinska A, Mkrtchyan A, Mkrtchyan H, Morgan N, Myers K, Narayan A, Ndukum L, Nelyubin V, Nuhait H, Nuruzzaman, van Oers W, Opper A, Page S, Pan J, Paschke K, Phillips S, Pitt M, Poelker M, Rajotte J, Ramsay W, Roche J, Sawatzky B, Seva T, Shabestari M, Silwal R, Simicevic N, Smith G, Solvignon P, Spayde D, Subedi A, Subedi R, Suleiman R, Tadevosyan V, Tobias W, Tvaskis V, Waidyawansa B, Wang P, Wells S, Wood S, Yang S, Young R, Zang P, Zhamkochyan S. Qweak: First Direct Measurement of the Proton’s Weak Charge. EPJ WEB OF CONFERENCES 2017. [DOI: 10.1051/epjconf/201713708005] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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6
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Sufian RS, Yang YB, Alexandru A, Draper T, Liang J, Liu KF. Strange Quark Magnetic Moment of the Nucleon at the Physical Point. PHYSICAL REVIEW LETTERS 2017; 118:042001. [PMID: 28186787 DOI: 10.1103/physrevlett.118.042001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/29/2016] [Indexed: 06/06/2023]
Abstract
We report a lattice QCD calculation of the strange quark contribution to the nucleon's magnetic moment and charge radius. This analysis presents the first direct determination of strange electromagnetic form factors including at the physical pion mass. We perform a model-independent extraction of the strange magnetic moment and the strange charge radius from the electromagnetic form factors in the momentum transfer range of 0.051 GeV^{2}≲Q^{2}≲1.31 GeV^{2}. The finite lattice spacing and finite volume corrections are included in a global fit with 24 valence quark masses on four lattices with different lattice spacings, different volumes, and four sea quark masses including one at the physical pion mass. We obtain the strange magnetic moment G_{M}^{s}(0)=-0.064(14)(09)μ_{N}. The four-sigma precision in statistics is achieved partly due to low-mode averaging of the quark loop and low-mode substitution to improve the statistics of the nucleon propagator. We also obtain the strange charge radius ⟨r_{s}^{2}⟩_{E}=-0.0043(16)(14) fm^{2}.
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Affiliation(s)
- Raza Sabbir Sufian
- Department of Physics and Astronomy, University of Kentucky, Lexington, Kentucky 40506, USA
| | - Yi-Bo Yang
- Department of Physics and Astronomy, University of Kentucky, Lexington, Kentucky 40506, USA
| | - Andrei Alexandru
- Department of Physics, The George Washington University, Washington, D.C. 20052, USA
| | - Terrence Draper
- Department of Physics and Astronomy, University of Kentucky, Lexington, Kentucky 40506, USA
| | - Jian Liang
- Department of Physics and Astronomy, University of Kentucky, Lexington, Kentucky 40506, USA
| | - Keh-Fei Liu
- Department of Physics and Astronomy, University of Kentucky, Lexington, Kentucky 40506, USA
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7
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Shanahan PE, Horsley R, Nakamura Y, Pleiter D, Rakow PEL, Schierholz G, Stüben H, Thomas AW, Young RD, Zanotti JM. Determination of the strange nucleon form factors. PHYSICAL REVIEW LETTERS 2015; 114:091802. [PMID: 25793800 DOI: 10.1103/physrevlett.114.091802] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/29/2014] [Indexed: 06/04/2023]
Abstract
The strange contribution to the electric and magnetic form factors of the nucleon is determined at a range of discrete values of Q^{2} up to 1.4 GeV^{2}. This is done by combining a recent analysis of lattice QCD results for the electromagnetic form factors of the octet baryons with experimental determinations of those quantities. The most precise result is a small negative value for the strange magnetic moment: G_{M}^{s}(Q^{2}=0)=-0.07±0.03μ_{N}. At larger values of Q^{2} both the electric and magnetic form factors are consistent with zero to within 2 standard deviations.
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Affiliation(s)
- P E Shanahan
- ARC Centre of Excellence in Particle Physics at the Terascale and CSSM, Department of Physics, University of Adelaide, Adelaide, SA 5005, Australia
| | - R Horsley
- School of Physics and Astronomy, University of Edinburgh, Edinburgh EH9 3JZ, United Kingdom
| | - Y Nakamura
- RIKEN Advanced Institute for Computational Science, Kobe, Hyogo 650-0047, Japan
| | - D Pleiter
- JSC, Forschungzentrum Jülich, 52425 Jülich, Germany
- Institut für Theoretische Physik, Universität Regensburg, 93040 Regensburg, Germany
| | - P E L Rakow
- Theoretical Physics Division, Department of Mathematical Sciences, University of Liverpool, Liverpool L69 3BX, United Kingdom
| | - G Schierholz
- Deutsches Elektronen-Synchrotron DESY, 22603 Hamburg, Germany
| | - H Stüben
- Regionales Rechenzentrum, Universität Hamburg, 20146 Hamburg, Germany
| | - A W Thomas
- ARC Centre of Excellence in Particle Physics at the Terascale and CSSM, Department of Physics, University of Adelaide, Adelaide, SA 5005, Australia
| | - R D Young
- ARC Centre of Excellence in Particle Physics at the Terascale and CSSM, Department of Physics, University of Adelaide, Adelaide, SA 5005, Australia
| | - J M Zanotti
- ARC Centre of Excellence in Particle Physics at the Terascale and CSSM, Department of Physics, University of Adelaide, Adelaide, SA 5005, Australia
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8
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Marinelli JR, Graeff CA. Nucleon size effects in the parity violating electron scattering asymmetry. EPJ WEB OF CONFERENCES 2014. [DOI: 10.1051/epjconf/20146602068] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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9
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Pate S, Trujillo D. Strangeness Vector and Axial-Vector Form Factors of the Nucleon. EPJ WEB OF CONFERENCES 2014. [DOI: 10.1051/epjconf/20146606018] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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10
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Androic D, Armstrong D, Asaturyan A, Averett T, Balewski J, Beaufait J, Beminiwattha R, Benesch J, Benmokhtar F, Birchall J, Carlini R, Cates G, Cornejo J, Covrig S, Dalton M, Davis C, Deconinck W, Diefenbach J, Dowd J, Dunne J, Dutta D, Duvall W, Elaasar M, Falk W, Finn J, Forest T, Gaskell D, Gericke M, Grames J, Gray V, Grimm K, Guo F, Hoskins J, Johnston K, Jones D, Jones M, Jones R, Kargiantoulakis M, King P, Korkmaz E, Kowalski S, Leacock J, Leckey J, Lee A, Lee J, Lee L, MacEwan S, Mack D, Magee J, Mahurin R, Mammei J, Martin J, McHugh M, Meekins D, Mei J, Michaels R, Micherdzinska A, Mkrtchyan A, Mkrtchyan H, Morgan N, Myers K, Narayan A, Ndukum L, Nelyubin V, Nuruzzaman, van Oers W, Opper A, Page S, Pan J, Paschke K, Phillips S, Pitt M, Poelker M, Rajotte J, Ramsay W, Roche J, Sawatzky B, Seva T, Shabestari M, Silwal R, Simicevic N, Smith G, Solvignon P, Spayde D, Subedi A, Subedi R, Suleiman R, Tadevosyan V, Tobias W, Tvaskis V, Waidyawansa B, Wang P, Wells S, Wood S, Yang S, Young R, Zhamkochyan S. Early Results from the QweakExperiment. EPJ WEB OF CONFERENCES 2014. [DOI: 10.1051/epjconf/20146605002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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11
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Nuruzzaman. Qweak: First Direct Measurement of the Weak Charge of the Proton. EPJ WEB OF CONFERENCES 2014. [DOI: 10.1051/epjconf/20147100100] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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12
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13
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Androic D, Armstrong DS, Asaturyan A, Averett T, Balewski J, Beaufait J, Beminiwattha RS, Benesch J, Benmokhtar F, Birchall J, Carlini RD, Cates GD, Cornejo JC, Covrig S, Dalton MM, Davis CA, Deconinck W, Diefenbach J, Dowd JF, Dunne JA, Dutta D, Duvall WS, Elaasar M, Falk WR, Finn JM, Forest T, Gaskell D, Gericke MTW, Grames J, Gray VM, Grimm K, Guo F, Hoskins JR, Johnston K, Jones D, Jones M, Jones R, Kargiantoulakis M, King PM, Korkmaz E, Kowalski S, Leacock J, Leckey J, Lee AR, Lee JH, Lee L, MacEwan S, Mack D, Magee JA, Mahurin R, Mammei J, Martin JW, McHugh MJ, Meekins D, Mei J, Michaels R, Micherdzinska A, Mkrtchyan A, Mkrtchyan H, Morgan N, Myers KE, Narayan A, Ndukum LZ, Nelyubin V, van Oers WTH, Opper AK, Page SA, Pan J, Paschke KD, Phillips SK, Pitt ML, Poelker M, Rajotte JF, Ramsay WD, Roche J, Sawatzky B, Seva T, Shabestari MH, Silwal R, Simicevic N, Smith GR, Solvignon P, Spayde DT, Subedi A, Subedi R, Suleiman R, Tadevosyan V, Tobias WA, Tvaskis V, Waidyawansa B, Wang P, Wells SP, Wood SA, Yang S, Young RD, Zhamkochyan S. First determination of the weak charge of the proton. PHYSICAL REVIEW LETTERS 2013; 111:141803. [PMID: 24152148 DOI: 10.1103/physrevlett.111.141803] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/25/2013] [Indexed: 06/02/2023]
Abstract
The Q(weak) experiment has measured the parity-violating asymmetry in ep elastic scattering at Q(2)=0.025(GeV/c)(2), employing 145 μA of 89% longitudinally polarized electrons on a 34.4 cm long liquid hydrogen target at Jefferson Lab. The results of the experiment's commissioning run, constituting approximately 4% of the data collected in the experiment, are reported here. From these initial results, the measured asymmetry is A(ep)=-279±35 (stat) ± 31 (syst) ppb, which is the smallest and most precise asymmetry ever measured in ep scattering. The small Q(2) of this experiment has made possible the first determination of the weak charge of the proton Q(W)(p) by incorporating earlier parity-violating electron scattering (PVES) data at higher Q(2) to constrain hadronic corrections. The value of Q(W)(p) obtained in this way is Q(W)(p)(PVES)=0.064±0.012, which is in good agreement with the standard model prediction of Q(W)(p)(SM)=0.0710±0.0007. When this result is further combined with the Cs atomic parity violation (APV) measurement, significant constraints on the weak charges of the up and down quarks can also be extracted. That PVES+APV analysis reveals the neutron's weak charge to be Q(W)(n)(PVES+APV)=-0.975±0.010.
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Affiliation(s)
- D Androic
- University of Zagreb, Zagreb HR-10002, Croatia
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14
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Wang D, Pan K, Subedi R, Deng X, Ahmed Z, Allada K, Aniol KA, Armstrong DS, Arrington J, Bellini V, Beminiwattha R, Benesch J, Benmokhtar F, Camsonne A, Canan M, Cates GD, Chen JP, Chudakov E, Cisbani E, Dalton MM, de Jager CW, De Leo R, Deconinck W, Deur A, Dutta C, El Fassi L, Flay D, Franklin GB, Friend M, Frullani S, Garibaldi F, Giusa A, Glamazdin A, Golge S, Grimm K, Hafidi K, Hansen O, Higinbotham DW, Holmes R, Holmstrom T, Holt RJ, Huang J, Hyde CE, Jen CM, Jones D, Kang H, King P, Kowalski S, Kumar KS, Lee JH, LeRose JJ, Liyanage N, Long E, McNulty D, Margaziotis DJ, Meddi F, Meekins DG, Mercado L, Meziani ZE, Michaels R, Mihovilovic M, Muangma N, Myers KE, Nanda S, Narayan A, Nelyubin V, Oh Y, Parno D, Paschke KD, Phillips SK, Qian X, Qiang Y, Quinn B, Rakhman A, Reimer PE, Rider K, Riordan S, Roche J, Rubin J, Russo G, Saenboonruang K, Saha A, Sawatzky B, Shahinyan A, Silwal R, Sirca S, Souder PA, Suleiman R, Sulkosky V, Sutera CM, Tobias WA, Urciuoli GM, Waidyawansa B, Wojtsekhowski B, Ye L, Zhao B, Zheng X. Measurements of parity-violating asymmetries in electron-deuteron scattering in the nucleon resonance region. PHYSICAL REVIEW LETTERS 2013; 111:082501. [PMID: 24016222 DOI: 10.1103/physrevlett.111.082501] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/29/2013] [Indexed: 06/02/2023]
Abstract
We report on parity-violating asymmetries in the nucleon resonance region measured using inclusive inelastic scattering of 5-6 GeV longitudinally polarized electrons off an unpolarized deuterium target. These results are the first parity-violating asymmetry data in the resonance region beyond the Δ(1232). They provide a verification of quark-hadron duality-the equivalence of the quark- and hadron-based pictures of the nucleon-at the (10-15)% level in this electroweak observable, which is dominated by contributions from the nucleon electroweak γZ interference structure functions. In addition, the results provide constraints on nucleon resonance models relevant for calculating background corrections to elastic parity-violating electron scattering measurements.
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Affiliation(s)
- D Wang
- University of Virginia, Charlottesville, Virginia 22904, USA
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15
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Abrahamyan S, Ahmed Z, Albataineh H, Aniol K, Armstrong DS, Armstrong W, Averett T, Babineau B, Barbieri A, Bellini V, Beminiwattha R, Benesch J, Benmokhtar F, Bielarski T, Boeglin W, Camsonne A, Canan M, Carter P, Cates GD, Chen C, Chen JP, Hen O, Cusanno F, Dalton MM, De Leo R, de Jager K, Deconinck W, Decowski P, Deng X, Deur A, Dutta D, Etile A, Flay D, Franklin GB, Friend M, Frullani S, Fuchey E, Garibaldi F, Gasser E, Gilman R, Giusa A, Glamazdin A, Gomez J, Grames J, Gu C, Hansen O, Hansknecht J, Higinbotham DW, Holmes RS, Holmstrom T, Horowitz CJ, Hoskins J, Huang J, Hyde CE, Itard F, Jen CM, Jensen E, Jin G, Johnston S, Kelleher A, Kliakhandler K, King PM, Kowalski S, Kumar KS, Leacock J, Leckey J, Lee JH, LeRose JJ, Lindgren R, Liyanage N, Lubinsky N, Mammei J, Mammoliti F, Margaziotis DJ, Markowitz P, McCreary A, McNulty D, Mercado L, Meziani ZE, Michaels RW, Mihovilovic M, Muangma N, Muñoz-Camacho C, Nanda S, Nelyubin V, Nuruzzaman N, Oh Y, Palmer A, Parno D, Paschke KD, Phillips SK, Poelker B, Pomatsalyuk R, Posik M, Puckett AJR, Quinn B, Rakhman A, Reimer PE, Riordan S, Rogan P, Ron G, Russo G, Saenboonruang K, Saha A, Sawatzky B, Shahinyan A, Silwal R, Sirca S, Slifer K, Solvignon P, Souder PA, Sperduto ML, Subedi R, Suleiman R, Sulkosky V, Sutera CM, Tobias WA, Troth W, Urciuoli GM, Waidyawansa B, Wang D, Wexler J, Wilson R, Wojtsekhowski B, Yan X, Yao H, Ye Y, Ye Z, Yim V, Zana L, Zhan X, Zhang J, Zhang Y, Zheng X, Zhu P. Measurement of the neutron radius of 208Pb through parity violation in electron scattering. PHYSICAL REVIEW LETTERS 2012; 108:112502. [PMID: 22540469 DOI: 10.1103/physrevlett.108.112502] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/12/2012] [Indexed: 05/31/2023]
Abstract
We report the first measurement of the parity-violating asymmetry A(PV) in the elastic scattering of polarized electrons from 208Pb. A(PV) is sensitive to the radius of the neutron distribution (R(n)). The result A(PV)=0.656±0.060(stat)±0.014(syst) ppm corresponds to a difference between the radii of the neutron and proton distributions R(n)-R(p)=0.33(-0.18)(+0.16) fm and provides the first electroweak observation of the neutron skin which is expected in a heavy, neutron-rich nucleus.
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16
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Young RD, Carlini RD, Thomas AW, Roche J. Testing the standard model by precision measurement of the weak charges of quarks. PHYSICAL REVIEW LETTERS 2007; 99:122003. [PMID: 17930499 DOI: 10.1103/physrevlett.99.122003] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/23/2007] [Indexed: 05/25/2023]
Abstract
In a global analysis of the latest parity-violating electron scattering measurements on nuclear targets, we demonstrate a significant improvement in the experimental knowledge of the weak neutral-current lepton-quark interactions at low energy. The precision of this new result, combined with earlier atomic parity-violation measurements, places tight constraints on the size of possible contributions from physics beyond the standard model. Consequently, this result improves the lower-bound on the scale of relevant new physics to approximately 1 TeV.
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Affiliation(s)
- R D Young
- Jefferson Lab, 12000 Jefferson Ave., Newport News, Virginia 23606, USA
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17
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Viviani M, Schiavilla R, Kubis B, Lewis R, Girlanda L, Kievsky A, Marcucci LE, Rosati S. Isospin mixing in the nucleon and 4He and the nucleon strange electric form factor. PHYSICAL REVIEW LETTERS 2007; 99:112002. [PMID: 17930429 DOI: 10.1103/physrevlett.99.112002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/15/2007] [Indexed: 05/25/2023]
Abstract
In order to isolate the contribution of the nucleon strange electric form factor to the parity-violating asymmetry measured in 4He(e-->],e')4He experiments, it is crucial to have a reliable estimate of the magnitude of isospin-symmetry-breaking (ISB) corrections in both the nucleon and 4He. We examine this issue in the present Letter. Isospin admixtures in the nucleon are determined in chiral perturbation theory, while those in 4He are derived from nuclear interactions, including explicit ISB terms. A careful analysis of the model dependence in the resulting predictions for the nucleon and nuclear ISB contributions to the asymmetry is carried out. We conclude that, at the low momentum transfers of interest in recent measurements reported by the HAPPEX Collaboration at Jefferson Lab, these contributions are of comparable magnitude to those associated with strangeness components in the nucleon electric form factor.
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Affiliation(s)
- M Viviani
- INFN, Sezione di Pisa, and Department of Physics, University of Pisa, I-56127 Pisa, Italy
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18
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Dillon G, Morpurgo G. Baryon octet magnetic moments to all orders in flavor breaking: An application to the problem of the strangeness in the nucleon. Int J Clin Exp Med 2007. [DOI: 10.1103/physrevd.75.073007] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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19
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Acha A, Aniol KA, Armstrong DS, Arrington J, Averett T, Bailey SL, Barber J, Beck A, Benaoum H, Benesch J, Bertin PY, Bosted P, Butaru F, Burtin E, Cates GD, Chao YC, Chen JP, Chudakov E, Cisbani E, Craver B, Cusanno F, De Leo R, Decowski P, Deur A, Feuerbach RJ, Finn JM, Frullani S, Fuchs SA, Fuoti K, Gilman R, Glesener LE, Grimm K, Grames JM, Hansen JO, Hansknecht J, Higinbotham DW, Holmes R, Holmstrom T, Ibrahim H, de Jager CW, Jiang X, Katich J, Kaufman LJ, Kelleher A, King PM, Kolarkar A, Kowalski S, Kuchina E, Kumar KS, Lagamba L, LaViolette P, LeRose J, Lindgren RA, Lhuillier D, Liyanage N, Margaziotis DJ, Markowitz P, Meekins DG, Meziani ZE, Michaels R, Moffit B, Nanda S, Nelyubin V, Otis K, Paschke KD, Phillips SK, Poelker M, Pomatsalyuk R, Potokar M, Prok Y, Puckett A, Qian X, Qiang Y, Reitz B, Roche J, Saha A, Sawatzky B, Singh J, Slifer K, Sirca S, Snyder R, Solvignon P, Souder PA, Stutzman ML, Subedi R, Suleiman R, Sulkosky V, Tobias WA, Ulmer PE, Urciuoli GM, Wang K, Whitbeck A, Wilson R, Wojtsekhowski B, Yao H, Ye Y, Zhan X, Zheng X, Zhou S, Ziskin V. Precision measurements of the nucleon strange form factors at Q2 approximately 0.1 GeV2. PHYSICAL REVIEW LETTERS 2007; 98:032301. [PMID: 17358678 DOI: 10.1103/physrevlett.98.032301] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/06/2006] [Indexed: 05/14/2023]
Abstract
We report new measurements of the parity-violating asymmetry A(PV) in elastic scattering of 3 GeV electrons off hydrogen and 4He targets with <theta(lab)> approximately 6.0 degrees . The 4He result is A(PV)=(+6.40+/-0.23(stat)+/-0.12(syst))x10(-6). The hydrogen result is A(PV)=(-1.58+/-0.12(stat)+/-0.04(syst))x10(-6). These results significantly improve constraints on the electric and magnetic strange form factors G(E)(s) and G(M)(s). We extract G(E)(s)=0.002+/-0.014+/-0.007 at <Q(2)>=0.077 GeV2, and G(E)(s)+0.09G(M)(s)=0.007+/-0.011+/-0.006 at <Q(2)>=0.109 GeV2, providing new limits on the role of strange quarks in the nucleon charge and magnetization distributions.
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Affiliation(s)
- A Acha
- Florida International University, Miami, Florida 33199, USA
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Young RD, Roche J, Carlini RD, Thomas AW. Extracting nucleon strange and anapole form factors from world data. PHYSICAL REVIEW LETTERS 2006; 97:102002. [PMID: 17025805 DOI: 10.1103/physrevlett.97.102002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/19/2006] [Indexed: 05/12/2023]
Abstract
The complete world set of parity-violating electron scattering data up to Q2 approximately 0.3 GeV2 is analyzed. We extract the current experimental determination of the strange electric and magnetic form factors of the proton, as well as the weak axial form factors of the proton and neutron, at Q2=0.1 GeV2. Within experimental uncertainties, we find that the strange form factors are consistent with zero, as are the anapole contributions to the axial form factors. Nevertheless, the correlation between the strange and anapole contributions suggest that there is only a small probability that these form factors all vanish simultaneously.
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Affiliation(s)
- R D Young
- Jefferson Lab, 12000 Jefferson Avenue, Newport News, Virginia 23606, USA
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Silva A, Kim HC, Urbano D, Goeke K. Parity-violating asymmetries in elastice→pscattering in the chiral quark-soliton model: Comparison with the A4, G0, HAPPEX and SAMPLE experiments. Int J Clin Exp Med 2006. [DOI: 10.1103/physrevd.74.054011] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Leinweber DB, Boinepalli S, Thomas AW, Wang P, Williams AG, Young RD, Zanotti JM, Zhang JB. Strange electric form factor of the proton. PHYSICAL REVIEW LETTERS 2006; 97:022001. [PMID: 16907436 DOI: 10.1103/physrevlett.97.022001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/20/2006] [Indexed: 05/11/2023]
Abstract
By combining the constraints of charge symmetry with new chiral extrapolation techniques and recent low-mass quenched lattice QCD simulations of the individual quark contributions to the electric charge radii of the baryon octet, we obtain an accurate determination of the strange electric charge radius of the proton. While this analysis provides a value for G(E)(s)(Q(2) = 0.1 GeV(2)) in agreement with the best current data, the theoretical error is comparable with that expected from future HAPPEX results from JLab. Together with the earlier determination of G(M)(s), this result considerably constrains the role of hidden flavor in the structure of the nucleon.
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Affiliation(s)
- D B Leinweber
- Special Research Centre for the Subatomic Structure of Matter, and Department of Physics, University of Adelaide, Adelaide SA 5005, Australia
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