Nuclear Theory·nucl-th

Tuesday·July 11, 2017

10 papers—5 primary·5 cross-listed

06
Anomalous current from covariant Wigner functions
George Prokhorov🇷🇺 · Oleg Teryaev🇷🇺
We consider accelerated and rotating media of weakly interacting fermions in local thermodynamic equilibrium. Kinetic properties of this media are described by covariant Wigner function calculated on the basis of relativistic distribution function of particles with spin. We obtain the formulae for axial current beyond the approximation of smallness of thermal vorticity tensor and chemical potential and calculate its divergence. In the massless limit higher order terms in vorticity and chemical potential compensate each other with only the low-order contributions surviving. It is shown, that axial current gets a topological component along the 4-acceleration vector. The similarity between different approaches to baryon polarisation is established.
↳ hep-thhep-phnucl-thPRD(2018)·30 citations
07
Heavy sterile neutrino in dark matter searches
Paraskevi C. Divari🇬🇷 · John D. Vergados🇬🇷
Sterile neutrinos are possible dark matter candidates. We examine here possible detection mechanisms, assuming that the neutrino has a mass of about 50 keV and couples to the ordinary neutrino. Even though this neutrino is quite heavy, it is non relativistic with a maximum kinetic energy of 0.1 eV. Thus new experimental techniques are required for its detection. We estimate the expected event rate in the following cases: i) Measure electron recoils in the case of materials with very low electron binding. ii) Low temperature crystal bolometers. iii) Spin induced atomic excitations at very low temperatures, leading to a characteristic photon spectrum. iv) Observation of resonances in antineutrino absorption by a nucleus undergoing electron capture. v) Neutrino induced electron events beyond the end point energy of beta decaying systems, e.g. in the tritium decay studied by KATRIN.
↳ hep-phastro-ph.HEnucl-thAdv.High Energy Phys.(2018)·6 citations
08
Magnetic moments of the doubly charmed and bottomed baryons
Hao-Song Li🇨🇳 · Lu Meng🇨🇳 · Zhan-Wei Liu🇨🇳 · Shi-Lin Zhu🇨🇳
The chiral corrections to the magnetic moments of the spin- $\frac{1}{2}$ doubly charmed baryons are systematically investigated up to next-to-next-to-leading order with heavy baryon chiral perturbation theory (HBChPT). The numerical results are calculated up to next-to-leading order: $μ_{Ξ_{cc}^{++}} = - 0.25 μ_{N}$ , $μ_{Ξ_{cc}^{+}} = 0.85 μ_{N}$ , $μ_{Ω_{cc}^{+}} = 0.78 μ_{N}$ . We also calculate the magnetic moments of the other doubly heavy baryons, including the doubly bottomed baryons (bbq) and the doubly heavy baryons containing a light quark, a charm quark and a bottom quark ( ${b c} q$ and $[b c] q$ ): $μ_{Ξ_{bb}^{0}} = - 0.84 μ_{N}$ , $μ_{Ξ_{bb}^{-}} = 0.26 μ_{N}$ , $μ_{Ω_{bb}^{-}} = 0.19 μ_{N}$ , $μ_{Ξ_{{b c} q}^{+}} = - 0.54 μ_{N}$ , $μ_{Ξ_{{b c} q}^{0}} = 0.56 μ_{N}$ , $μ_{Ω_{{b c} q}^{0}} = 0.49 μ_{N}$ , $μ_{Ξ_{[b c] q}^{+}} = 0.69 μ_{N}$ , $μ_{Ξ_{[b c] q}^{0}} = - 0.59 μ_{N}$ , $μ_{Ω_{[b c] q}^{0}} = 0.24 μ_{N}$ .
↳ hep-phhep-exhep-latnucl-ex+1PRD(2017)·66 citations
09
Probing Saturation Physics in the Real Compton Scattering at Ultraperipheral $pP b$ Collisions
V. P. Goncalves🇧🇷 · F. S. Navarra🇧🇷 · D. Spiering🇧🇷
The Real Compton Scattering in ultraperipheral $pP b$ collisions at RHIC and LHC energies is investigated and predictions for the squared transverse momentum ( $t$ ) and rapidity ( $Y$ ) distributions are presented. The scattering amplitude is assumed to be given by the sum of the Reggeon and Pomeron contributions and the Pomeron one is described by the Color Dipole formalism taking into account the non - linear (saturation) effects in the QCD dynamics. We demonstrate that the behaviour of the cross sections at large -- $t$ and/or $Y$ is dominated by the Pomeron contribution and is strongly affected by the non -- linear effects present in the QCD dynamics. These results indicate that a future experimental analysis of this process can be useful to probe the QCD dynamics at high energies.
↳ hep-phhep-exnucl-exnucl-thPLB(2017)·2 citations
10
One-loop QCD thermodynamics in a strong homogeneous and static magnetic field
Shubhalaxmi Rath🇮🇳 · Binoy Krishna Patra🇮🇳
We have studied how the equation of state of thermal QCD with two light flavours is modified in strong magnetic field by calculating the thermodynamic observables of hot QCD matter up to one-loop, where the magnetic field affects mainly the quark contribution and the gluonic part is largely unaffected except for the softening of the screening mass due to the strong magnetic field. To begin with the effect of magnetic field on the thermodynamics, we have first calculated the pressure of a thermal QCD medium in strong magnetic field limit (SML), where the pressure at fixed temperature increases with the magnetic field faster than the increase with the temperature at constant magnetic field. This can be envisaged from the dominant scale of thermal medium in SML, which is the magnetic field, like the temperature in thermal medium in absence of strong magnetic field. Thus although the presence of strong magnetic field makes the pressure of hot QCD medium harder but the increase of pressure with respect to the temperature becomes less steeper. Corroborated to the above observations, the entropy density is found to decrease with the temperature in the ambience of strong magnetic field which resonates with the fact that the strong magnetic field restricts the dynamics of quarks in two dimensions, hence the phase space gets squeezed resulting the reduction of number of microstates. Moreover the energy density is seen to decrease and the speed of sound of thermal QCD medium is increased in the presence of strong magnetic field. These crucial findings in strong magnetic field could have phenomenological implications in heavy ion collisions because the expansion dynamics of the medium produced in noncentral ultrarelativistic heavy ion collisions is effectively controlled by both the energy density and the speed of sound.
↳ hep-thhep-phnucl-thJHEP(2017)·62 citations

Affiliations

first authorsco-authorsvia INSPIRE

Anomalous current from covariant Wigner functions

Heavy sterile neutrino in dark matter searches

Magnetic moments of the doubly charmed and bottomed baryons

Probing Saturation Physics in the Real Compton Scattering at Ultraperipheral pPb Collisions

One-loop QCD thermodynamics in a strong homogeneous and static magnetic field

Affiliations

Probing Saturation Physics in the Real Compton Scattering at Ultraperipheral $pP b$ Collisions