Nuclear Theory·nucl-th

Thursday·March 5, 2015

8 papers—3 primary·5 cross-listed

04
Charge Symmetry Violation in the Electromagnetic Form Factors of the Proton
P. E. Shanahan🇦🇺 · R. Horsley🇬🇧 · Y. Nakamura🇯🇵 · D. Pleiter🇩🇪 · P. E. L. Rakow🇬🇧 · G. Schierholz🇩🇪 · H. Stüben🇩🇪 · A. W. Thomas🇦🇺 · R. D. Young🇦🇺 · J. M. Zanotti🇦🇺
Experimental tests of QCD through its predictions for the strange-quark content of the proton have been drastically restricted by our lack of knowledge of the violation of charge symmetry (CSV). We find unexpectedly tiny CSV in the proton's electromagnetic form factors by performing the first extraction of these quantities based on an analysis of lattice QCD data. The resulting values are an order of magnitude smaller than current bounds on proton strangeness from parity violating electron-proton scattering experiments. This result paves the way for a new generation of experimental measurements of the proton's strange form factors to challenge the predictions of QCD.
↳ hep-lathep-phnucl-thPRD(2015)·12 citations
05
Neutrino astrophysics : recent advances and open issues
Cristina Volpe🇫🇷
We highlight recent advances in neutrino astrophysics, the open issues and the interplay with neutrino properties. We emphasize the important progress in our understanding of neutrino flavor conversion in media. We discuss the case of solar neutrinos, of core-collapse supernova neutrinos and of SN1987A, and of the recently discovered ultra-high energy neutrinos whose origin is to be determined.
↳ astro-ph.SRastro-ph.HEhep-phnucl-thJ.Phys.Conf.Ser.(2015)·7 citations
06
Lepton universality test in the photoproduction of $e^{-} e^{+}$ versus $μ^{-} μ^{+}$ pairs on a proton target
Vladyslav Pauk🇩🇪 · Marc Vanderhaeghen🇩🇪
In view of the significantly different proton charge radius extracted from muonic hydrogen Lamb shift measurements as compared to electronic hydrogen spectroscopy or electron scattering experiments, we study in this work the photoproduction of a lepton pair on a proton target in the limit of very small momentum transfer as a way to provide a test of the lepton universality when extracting the proton charge form factor. By detecting the recoiling proton in the $γ p \to l^{-} l^{+} p$ reaction, we show that a measurement of a ratio of $e^{-} e^{+} + μ^{-} μ^{+}$ over $e^{-} e^{+}$ cross sections with a relative precision of around 2%, would allow for a test to distinguish between the two different proton charge radii currently extracted from muonic and electronic observables.
↳ hep-phnucl-thPRL(2015)·24 citations
07
Precise measurement of branching ratios in the beta decay of 38Ca
H. I. Park🇺🇸 · J. C. Hardy🇺🇸 · V. E. Iacob🇺🇸 · M. Bencomo🇺🇸 · L. Chen🇺🇸 · V. Horvat🇺🇸 · N. Nica🇺🇸 · B. T. Roeder🇺🇸 · E. McCleskey🇺🇸 · R. E. Tribble🇺🇸 · I. S. Towner🇺🇸
We present the full description of a measurement of the branching ratios for the beta-decay of 38Ca. This decay includes five allowed 0+ --> 1+ branches and a superallowed 0+ --> 0+ one. With our new result for the latter, we determine its ft value to be 3062.3(68) s, a result whose precision (0.2%) is comparable to the precision of the thirteen well known 0+ --> 0+ transitions used up till now for the determination of Vud, the up-down quark-mixing element of the CKM matrix. The 38Ca superallowed transition thus becomes the first addition to this set of transitions in nearly a decade and the first for which a precise mirror comparison is possible, thus enabling an improved test of the isospin-symmetry-breaking corrections required for the extraction of Vud.
↳ nucl-exhep-phnucl-thPRC(2015)·16 citations
08
The Structure of the Nucleon: Elastic Electromagnetic Form Factors
V. Punjabi🇺🇸 · C.F. Perdrisat🇺🇸 · M.K. Jones🇺🇸 · E.J. Brash🇺🇸 · C.E. Carlson🇺🇸
Precise proton and neutron form factor measurements at Jefferson Lab, using spin observables, have recently made a significant contribution to the unraveling of the internal structure of the nucleon. Accurate experimental measurements of the nucleon form factors are a test-bed for understanding how the nucleon's static properties and dynamical behavior emerge from QCD, the theory of the strong interactions between quarks. There has been enormous theoretical progress, since the publication of the Jefferson Lab proton form factor ratio data, aiming at reevaluating the picture of the nucleon. We will review the experimental and theoretical developments in this field and discuss the outlook for the future.
↳ nucl-exnucl-thEPJA(2015)·262 citations

Affiliations

first authorsco-authorsvia INSPIRE

Charge Symmetry Violation in the Electromagnetic Form Factors of the Proton

Neutrino astrophysics : recent advances and open issues

Lepton universality test in the photoproduction of e−e+ versus μ−μ+ pairs on a proton target

Precise measurement of branching ratios in the beta decay of 38Ca

The Structure of the Nucleon: Elastic Electromagnetic Form Factors

Affiliations

Lepton universality test in the photoproduction of $e^{-} e^{+}$ versus $μ^{-} μ^{+}$ pairs on a proton target