Nuclear Theory·nucl-th

Monday·October 8, 2018

13 papers—7 primary·6 cross-listed

08
P-wave heavy quarkonium spectrum with next-to-next-to-next-to-leading logarithmic accuracy
Clara Peset🇩🇪 · Antonio Pineda🇪🇸 · Jorge Segovia🇪🇸
We compute the heavy quarkonium mass of $l \neq = 0$ (angular momentum) states, with otherwise arbitrary quantum numbers, with next-next-to-next-to-leading logarithmic (N $^{3}$ LL) accuracy. This constitutes the first observable in heavy quarkonium for which two orders of the weak-coupling expansion sensitive to the ultrasoft scale are known and the resummation of ultrasoft logarithms is made. We also obtain, for the first time, resummed N $^{3}$ LL expressions for the different fine and hyperfine energy splittings of these states, which are not sensitive to the ultrasoft scale but still require resummation of (hard) logarithms. We do this analysis for the equal and non-equal mass cases. We also study an alternative computational scheme that treats the static potential exactly. We then perform a comprehensive phenomenological analysis: we apply these results to the $n = 2$ , $l = 1$ bottomonium, $B_{c}$ and charmonium systems and study their convergence.
↳ hep-phhep-latnucl-thPRD(2018)·26 citations
09
Axion cooling of neutron stars. II. Beyond hadronic axions
Armen Sedrakian (FIAS)🇩🇪
We study the axion cooling of neutron stars within the Dine-Fischler-Srednicki-Zhitnitsky (DFSZ) model, which allows for tree level coupling of electrons to the axion {and locks the Peccei-Quinn charges of fermions via an angle parameter}. This extends our previous study [Phys. Rev. D 93, 065044 (2016)] limited to hadronic models of axions. We explore the two-dimensional space of axion parameters within the DFSZ model by comparing the theoretical cooling models with the surface temperatures of a few stars with measured surface temperatures. It is found that axions masses $m_{a} \geq 0.06$ to 0.12 eV can be excluded by x-ray observations of thermal emission of neutron stars (in particular by those of Cas A), the precise limiting value depending on the angle parameter of the DFSZ model. It is also found that axion emission by electron bremsstrahlung in neutron star crusts is negligible except for the special case where neutron Peccei-Quinn charge is small enough, so that the coupling of neutrons to axions can be neglected.
↳ astro-ph.HEnucl-thPRD(2019)·81 citations
10
Insight into Multiple Partonic Interactions and Production of Charmonia in p+p Collisions at the LHC energies
Raghunath Sahoo🇮🇳 · Dhananjaya Thakur🇮🇳 · Sudipan De🇮🇳 · Soumya Dansana🇮🇳
At the LHC energies, the underlying observables are of major topic of interest in high multiplicity $p + p$ collisions. Multiple Parton Interactions (MPI) is one of them, in which several interactions occur in a single $p + p$ collision. It is believed that MPI is the main reason behind the high multiplicity in $p + p$ collisions at the LHC. It was believed that MPI has only effect to the soft particle production, but recent ALICE result reveals that it can also affect the hard-particle production. In such case, the self normalized yield of heavy particle like $J/ ψ$ shows an increasing trend with event multiplicity. In the present contribution, we discuss the energy and multiplicity dependence of charmonium production to understand the effects of MPI on charmonium production.
↳ hep-phhep-exnucl-exnucl-thSpringer Proc.Phys.(2019)·1 citation
11
Time reversal violating Magnetic Quadrupole Moment in heavy deformed nuclei
B. G. C. Lackenby🇦🇺 · V. V. Flambaum🇦🇺
The existence of permanent electric dipole moments (EDMs) and magnetic quadrupole moments (MQMs) violate both time reversal invariance ( $T$ ) and parity ( $P$ ). Following the $C P T$ theorem they also violate combined $C P$ symmetry. Nuclear EDM are completely screened in atoms and molecules while interaction between electrons and MQM creates atomic and molecular EDM which can be measured and used to test CP-violation theories. Nuclear MQM are produced by the nucleon-nucleon $T, P$ -odd interaction and by nucleon EDM. In this work we study the effect of enhancement of the nuclear MQM due to the nuclear deformation. Using the Nilsson model we calculate the nuclear MQMs for deformed nuclei of experimental interest and the resultant MQM energy shift in diatomic molecules of experimental interest $^{173}$ YbF , $^{177, 179}$ HfF $^{+}$ , $^{181}$ TaN, $^{181}$ TaO $^{+}$ , $^{229}$ ThO and $^{229}$ ThF $^{+}$ .
↳ hep-phnucl-thphysics.atom-phPRD(2018)·29 citations
12
Electromagnetic proton-neutron mass difference
Oleksandr Tomalak🇩🇪
We discuss the Cottingham formula and evaluate the proton-neutron electromagnetic mass difference exploiting the state-of-the-art phenomenological input. We decompose individual contributions to the mass splitting into Born, inelastic and subtraction terms. We evaluate the subtraction-function contribution from the experimental input only and the Born term accounting for the modern low- $Q^{2}$ data.
↳ hep-phnucl-exnucl-thEur.Phys.J.Plus(2020)·10 citations
13
Resonant enhancement of oscillating electric field in atom
V.V. Flambaum🇦🇺 · I.B. Samsonov🇦🇺
When an atom is placed into an oscillating electric field with frequency far from atomic resonances, the atomic electrons partly shield this field at the nucleus. It is conjectured that when the frequency of electric field reaches an atomic resonance, the electric field at the nucleus may be significantly enhanced. In this paper, we systematically study the mechanisms of this enhancement and show that it may reach five orders in magnitude in particular cases. As an application, we consider laser-assisted neutron capture in 139-Lanthanum nucleus and screening and resonance enhancement of nuclear electromagnetic transitions by electrons.
↳ physics.atom-phhep-phnucl-thPRA(2018)·8 citations

Affiliations

first authorsco-authorsvia INSPIRE

P-wave heavy quarkonium spectrum with next-to-next-to-next-to-leading logarithmic accuracy

Axion cooling of neutron stars. II. Beyond hadronic axions

Insight into Multiple Partonic Interactions and Production of Charmonia in p+p Collisions at the LHC energies

Time reversal violating Magnetic Quadrupole Moment in heavy deformed nuclei

Electromagnetic proton-neutron mass difference

Resonant enhancement of oscillating electric field in atom

Affiliations