Nuclear Theory·nucl-th

Tuesday·December 22, 2015

23 papers—17 primary·6 cross-listed

18
PARTONS: PARtonic Tomography Of Nucleon Software. A computing framework for the phenomenology of Generalized Parton Distributions
B. Berthou🇫🇷 · D. Binosi🇮🇹 · N. Chouika🇫🇷 · L. Colaneri🇫🇷 · M. Guidal🇫🇷 · C. Mezrag🇺🇸 · H. Moutarde🇫🇷 · J. Rodríguez-Quintero🇪🇸 · F. Sabatié🇫🇷 · P. Sznajder🇫🇷 · J. Wagner🇵🇱
We describe the architecture and functionalities of a C++ software framework, coined PARTONS, dedicated to the phenomenology of Generalized Parton Distributions. These distributions describe the three-dimensional structure of hadrons in terms of quarks and gluons, and can be accessed in deeply exclusive lepto- or photo-production of mesons or photons. PARTONS provides a necessary bridge between models of Generalized Parton Distributions and experimental data collected in various exclusive production channels. We outline the specification of the PARTONS framework in terms of practical needs, physical content and numerical capacity. This framework will be useful for physicists - theorists or experimentalists - not only to develop new models, but also to interpret existing measurements and even design new experiments.
↳ hep-phhep-exnucl-exnucl-th+1EPJC(2018)·136 citations
19
Strong-coupling effects in a plasma of confining gluons
Wojciech Florkowski🇵🇱 · Radoslaw Ryblewski🇵🇱 · Nan Su🇩🇪 · Konrad Tywoniuk🇪🇸
The plasma consisting of confining gluons resulting from the Gribov quantization of the SU(3) Yang-Mills theory is studied using non-equilibrium fluid dynamical framework. Exploiting the Bjorken symmetry and using linear response theory a general analytic expressions for the bulk and shear viscosity coefficients are derived. It is found that the considered system exhibits a number of properties similar to the strongly-coupled theories, where the conformality is explicitly broken. In particular, it is shown that, in the large temperature limit, bulk to shear viscosity ratio, scales linearly with the difference $1/3 - c_{s}^{2}$ , where $c_{s}$ is the speed of sound. Results obtained from the analysis are in line with the interpretation of the quark-gluon plasma as an almost perfect fluid.
↳ hep-phhep-thnucl-thNPA(2016)·3 citations
20
Exclusive processes with a leading neutron in $e p$ collisions
V. P. Goncalves🇸🇪 · F. S. Navarra🇧🇷 · D. Spiering🇧🇷
In this paper we extend the color dipole formalism to the study of exclusive processes associated with a leading neutron in $e p$ collisions at high energies. The exclusive $ρ$ , $ϕ$ and $J /Ψ$ production, as well as the Deeply Virtual Compton Scattering, are analysed assuming a diffractive interaction between the color dipole and the pion emitted by the incident proton. We compare our predictions with the HERA data on $ρ$ production and estimate the magnitude of the absorption corrections. We show that the color dipole formalism is able to describe the current data. Finally, we present our estimate for the exclusive cross sections which can be studied at HERA and in future electron-proton colliders.
↳ hep-phhep-exnucl-thPRD(2016)·19 citations
21
Constituent-counting rule in photoproduction of hyperon resonances
Wen-Chen Chang (Taiwan, Inst. Phys.)🇹🇼 · S. Kumano (KEK, Tsukuba and J-PARC, Tokai)🇯🇵 · Takayasu Sekihara (RCNP, Osaka U.)🇯🇵
We analyze the CLAS data on the photoproduction of hyperon resonances, as well as the available data for the ground state $Λ$ and $Σ^{0}$ of the CLAS and SLAC-E84 collaborations, by considering constituent-counting rule suggested by perturbative QCD. The counting rule emerges as a scaling behavior of cross sections in hard exclusive reactions with large scattering angles, and it enables us to determine the number of elementary constituents inside hadrons. Therefore, it could be used as a new method for identifying internal constituents of exotic-hadron candidates. From the analyses of the $γ p \to K^{+} Λ$ and $K^{+} Σ^{0}$ reactions, we find that the number of the elementary constituents is consistent with $n_{γ} = 1$ , $n_{p} = 3$ , $n_{K^{+}} = 2$ , and $n_{Λ} = n_{Σ^{0}} = 3$ . Then, the analysis is made for the photoproductions of the hyperon resonances $Λ (1405)$ , $Σ (1385)^{0}$ , and $Λ (1520)$ , where $Λ (1405)$ is considered to be a $K ˉ N$ molecule and hence its constituent number could be five. However, we find that the current data are not enough to conclude the numbers of their constituent. It is necessary to investigate the higher-energy region at $s > 2.8$ GeV experimentally beyond the energy of the available CLAS data for counting the number of constituents clearly. We also mention that our results indicate energy dependence in the constituent number, especially for $Λ (1405)$ . If an excited hyperon is a mixture of three-quark and five-quark states, the energy dependence of the scaling behavior could be valuable for finding its composition and mixture.
↳ hep-phhep-exnucl-exnucl-thPRD(2016)·24 citations
22
Total kinetic energy release in the fast neutron-induced fission of $^{235}$ U
R. Yanez · W. Loveland · J. King · J.S. Barrett · N. Fotiades · H.Y. Lee
We have measured the total kinetic energy (TKE) release for the $^{235}$ U(n,f) reaction for $E_{n}$ =2-100 MeV using the 2E method with an array of Si PIN diode detectors. The neutron energies were determined by time of flight measurements using the white spectrum neutron beam at the LANSCE facility. (To calibrate the apparatus, the TKE release for $^{235}$ U(n $_{t h}$ ,f) was also measured using a thermal neutron beam from the OSU TRIGA reactor). The TKE decreases non-linearly from 169.0 MeV to 161.4 MeV for $E_{n}$ =2-90 MeV. The standard deviation of the TKE distribution is constant from $E_{n}$ =20-90 MeV. Comparison of the data with the multi-modal fission model of Brosa indicates the TKE decrease is a consequence of the growth of symmetric fission and the corresponding decrease of asymmetric fission with increasing neutron energy. The average TKE associated with the Brosa superlong, standard I and standard II modes for a given mass is independent of neutron energy.
↳ nucl-exnucl-thEPJA(2017)·16 citations
23
The 1/N expansion method in quantum field theory
H. Sazdjian🇫🇷
The motivations of the 1/N expansion method in quantum field theory are explained. The method is first illustrated with the O(N) model of scalar fields. A second example is considered with the two-dimensional Gross-Neveu model of fermion fields with global U(N) and discrete chiral symmetries. The case of QCD is briefly sketched.
↳ hep-thnucl-th3 citations

Affiliations

first authorsco-authorsvia INSPIRE

PARTONS: PARtonic Tomography Of Nucleon Software. A computing framework for the phenomenology of Generalized Parton Distributions

Strong-coupling effects in a plasma of confining gluons

Exclusive processes with a leading neutron in ep collisions

Constituent-counting rule in photoproduction of hyperon resonances

Total kinetic energy release in the fast neutron-induced fission of 235U

The 1/N expansion method in quantum field theory

Affiliations

Exclusive processes with a leading neutron in $e p$ collisions

Total kinetic energy release in the fast neutron-induced fission of $^{235}$ U