Search results for "Proton"
showing 10 items of 5886 documents
LHC-scale left-right symmetry and unification
2013
We construct a comprehensive list of nonsupersymmetric standard model extensions with a low-scale left-right (LR)-symmetric intermediate stage that may be obtained as simple low-energy effective theories within a class of renormalizable SO(10) grand unified theories. Unlike the traditional minimal LR models many of our example settings support a perfect gauge coupling unification even if the LR scale is in the LHC domain at a price of only (a few copies of) one or two types of extra fields pulled down to the TeV-scale ballpark. We discuss the main aspects of a potentially realistic model building conforming the basic constraints from the quark and lepton sector flavor structure, proton deca…
Proton Spin in Chiral Quark Models
1997
The spin and flavor fractions of constituent quarks in the proton are obtained from their chiral fluctuations involving Goldstone bosons. SU(3) flavor symmetry breaking suggested by the mass difference between the strange and up, down quarks is included, and this improves the agreement with the data markedly.
STRANGE HADRONS BRIDGE BETWEEN QUARKS AND STARS
2007
Future experimental opportunities for the hypernuclear physics at GSI/FAIR are presented. The HYPHI experiment will investigate exotic hypernuclei which are produced by nuclear collision with stable heavy ion beams and rare isotope beams (RI-beams) at GSI. Thanks to the use of [Formula: see text] beams and the skilful combination of experimental techniques, copious production of double Λ hypernuclei is expected at the PANDA experiment which will enable high precision γ spectroscopy for the first time. Finally a novel method to explore the interaction of antibaryons in nuclei by baryon-antibaryon pair production in antiproton nucleus interactions is outlined.
Tensor charges of light baryons in the Infinite Momentum Frame
2007
We have used the Chiral-Quark Soliton Model formulated in the Infinite Momentum Frame to investigate the octet, decuplet and antidecuplet tensor charges up to the 5Q level. Using flavor SU(3) symmetry we have obtained for the proton $\delta u=1.172$ and $\delta d=-0.315$ in fair agreement previous model estimations. The 5Q allowed us to estimate also the strange contribution to the proton tensor charge $\delta s=-0.011$. All those values have been obtained at the model scale Q^2=0.36 GeV^2.
Corrigendum to “Transverse extension of partons in the proton probed in the sea-quark range by measuring the DVCS cross section” [Phys. Lett. B 793 (…
2019
Physics letters / B B 800, 135129 (2020). doi:10.1016/j.physletb.2019.135129
Empirical transverse charge densities in the nucleon-to-P11(1440) transition
2009
Abstract Using recent experimental data, we analyze the electromagnetic transition from the nucleon to the P 11 ( 1440 ) resonance. From the resulting empirical transition form factors, we map out the quark transverse charge densities which induce the N → P 11 ( 1440 ) transition. It is found that the transition from the proton to its first radially excited state is dominated by up quarks in a central region of around 0.5 fm and by down quarks in an outer band which extends up to about 1 fm.
Spin on same-sign W -boson pair production
2019
We demonstrate that the LHC will be sensitive to quantum correlations between two quarks inside the proton. Same-sign W-boson pair production is the most promising channel for clear measurements of double parton scattering. The left-handed nature of the coupling between quarks and W-bosons makes it a prime probe to measure parton spin correlations. We perform a detailed analysis of double parton scattering, including relevant backgrounds. The analysis reveals that measurements comparing the rate at which two muons from W boson decays are produced in the same compared to opposite hemispheres are especially sensitive to spin correlations between two quarks inside the proton. We provide estima…
Measurement of the Forward-Backward Asymmetry in the Production ofB±Mesons inpp¯Collisions ats=1.96 TeV
2015
We present a measurement of the forward-backward asymmetry in the production of B-+/- mesons, A(FB)(B-+/-) using B-+/- -> J/ Psi K-+/- decays in 10.4 fb(-1) of p (p) over bar collisions at root s = 1.96 TeV collected by the D0 experiment during Run II of the Tevatron collider. A nonzero asymmetry would indicate a preference for a particular flavor, i.e., b quark or (b) over bar antiquark, to be produced in the direction of the proton beam. We extract A(FB) (B-+/-) from a maximum likelihood fit to the difference between the numbers of forward-and backward-produced B-+/- mesons. We measure an asymmetry consistent with zero: A(FB) (B-+/-) = [-0.24 +/- 0.41 (stat) +/- 0.19 (syst)] %.
Tomographic image of the proton
2016
We determine, based on the latest experimental Deep Virtual Compton Scattering experimental data, the dependence of the spatial size of the proton on the quark's longitudinal momentum. This results in a three-dimensional momentum-space image and tomography of the proton.
Cross section and longitudinal single-spin asymmetry AL for forward W±→μ±ν production in polarized p+p collisions at s=510 GeV
2018
We have measured the cross section and single-spin asymmetries from forward W±→μ±ν production in longitudinally polarized p+p collisions at s=510 GeV using the PHENIX detector at the Relativistic Heavy Ion Collider. The cross sections are consistent with previous measurements at this collision energy, while the most forward and backward longitudinal single spin asymmetries provide new insights into the sea quark helicities in the proton. The charge of the W bosons provides a natural flavor separation of the participating partons. © 2018 authors. Published by the American Physical Society.