Nuclear Theory·nucl-th

Friday·September 8, 2017

8 papers—4 primary·4 cross-listed

01
[Submitted on 7 Sept 2017]
High cumulants of conserved charges and their statistical uncertainties
Li-Zhu Chen🇨🇳 · Ye-Yin Zhao🇨🇳 · Xue Pan🇨🇳 · Zhi-Ming Li🇨🇳 · Yuan-Fang Wu🇨🇳
We study the influence of measured high cumulants of conserved charges on their associated statistical uncertainties in relativistic heavy-ion collisions. With a given number of events, the measured cumulants randomly fluctuate with an approximately normal distribution, while the estimated statistical uncertainties are found to be correlated with corresponding values of the obtained cumulants. Generally, with a given number of events, the larger the cumulants we measure, the larger the statistical uncertainties that are estimated. The error-weighted averaged cumulants are dependent on statistics. Despite this effect, however, it is found that the three sigma rule of thumb is still applicable when the statistics are above one million.
Comments:
5 pages, 3 figures. To be published in Chinese Physics C
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph)
arXiv:
1709.02056 [pdf]
CPC(2017)·3 citations
02
[Submitted on 7 Sept 2017]
Relation of $a^{†} a$ terms to higher-order terms in the adiabatic expansion for large-amplitude collective motion
Koichi Sato
We investigate the relation of $a^{†} a$ terms in the collective operator to the higher-order terms in the adiabatic self-consistent collective coordinate (ASCC) method. In the ASCC method, a state vector is written as $e^{i G^(q, p, n)} ∣ ϕ (q)⟩$ with $G^(q, p, n)$ which is a function of collective coordinate $q$ , its conjugate momentum $p$ and the particle number $n$ . According to the generalized Thouless theorem, $G^$ can be written as a linear combination of two-quasiparticle creation and annihilation operators $a_{μ}^{†} a_{ν}^{†}$ and $a_{ν} a_{μ}$ . We show that, if $a^{†} a$ terms are included in $G^(q, p, n)$ , it corresponds to the higher-order terms in the adiabatic expansion of $G^$ . This relation serves as a prescription to determine the higher-order collective operators from the $a^{†} a$ part of the collective operator, once it is given without solving the higher-order equations of motion.
Comments:
19 pages, no figure
Subjects:
Nuclear Theory (nucl-th)
arXiv:
1709.02090 [pdf]
PTEP(2017)·1 citation
03
[Submitted on 7 Sept 2017]
Thermodynamics and relativistic kinetic theory for q-generalized Bose-Einstein and Fermi-Dirac systems
Sukanya Mitra🇮🇳
The thermodynamics and covariant kinetic theory have been elaborately investigated in a non-extensive environment considering the non-extensive generalization of Bose-Einstein (BE) and Fermi-Dirac (FD) statistics. Starting with Tsallis' entropy formula, the fundamental principles of thermostatistics have been established for a grand canonical system having q-generalized BE/FD degrees of freedom. The many particle kinetic theory has been set up in terms of the relativistic transport equation with q-generalized Uehling-Uhlenbeck collision term. The conservation laws have been realized in terms of appropriate moments of the transport equation. The thermodynamic quantities have been obtained in weak non-extensive environment for a massive pion-nucleon and a massless quark-gluon system with non-zero baryon chemical potential. In order to get an estimate of the impact of non-extensivity on the system dynamics, the q-modified Debye mass and hence the q-modified effective coupling have been estimated for a quark-gluon system.
Comments:
14 pages, 7 figures, two column
Subjects:
Nuclear Theory (nucl-th)
arXiv:
1709.02095 [pdf]
EPJC(2018)·17 citations
04
[Submitted on 7 Sept 2017]
Updated three-body model of $^{6}$ He $β$ decay into the $α$ + $d$ continuum
E.M. Tursunov · D. Baye · P. Descouvemont
The $β$ -decay process of the $^{6}$ He halo nucleus into the $α + d$ continuum is studied in an updated three-body model. The $^{6}$ He nucleus is described as an $α + n + n$ system in hyperspherical coordinates on a Lagrange-mesh. The shape and absolute values of the transition probability per time and energy units of new experiments are reproduced with a modified $α + d$ potential. The obtained total transition probabilities are $2.48 \times 1 0^{- 6}$ s $^{- 1}$ for the full energy region and $2.40 \times 1 0^{- 6}$ s $^{- 1}$ for the cut-off $E > 150$ keV. The strong cancellation between the internal and halo parts of the $β$ decay matrix element is a challenge for future {\it ab initio} calculations.
Comments:
4 pages, 3 figures
Subjects:
Nuclear Theory (nucl-th)
arXiv:
1709.02120 [pdf]
PRC(2018)·3 citations
05
[Submitted on 7 Sept 2017] (cross-list from hep-ph)
Observation of the isospin breaking decay $Υ (10860) \to Υ (1 S) f_{0} (980) \to Υ (1 S) η π^{0}$ with the Belle II detector
N.N. Achasov🇷🇺 · G.N. Shestakov🇷🇺
Using the Belle data on the decay $Υ (10860) \to Υ (1 S) f_{0} (980) \to Υ (1 S) π^{+} π^{-}$ , we estimate the fraction of the process $Υ (10860) \to Υ (1 S) f_{0} (980) \to Υ (1 S) η π^{0}$ , caused by the mixing of $a_{0}^{0} (980)$ and $f_{0} (980)$ resonances that breaks the isotopic invariance due to the $K^{+}$ and $K^{0}$ meson mass difference. With an instantaneous luminosity of $8 \times 1 0^{35}$ cm $^{2} \cdot$ \,s $^{- 1}$ at the SuperKEKB collider, one can collect with the Belle II detector about a hundred $Υ (10860) \to Υ (1 S) η π^{0}$ events in the narrow region of the $η π^{0}$ invariant mass near the $K K ˉ$ thresholds in a time roughly spent on the present Belle experiment.
Comments:
5 pages, 2 figures; the comment is added, Ref. [6], that the using of the Flatte propagators for the $f_{0} (980)$ and $a_{0} (980)$ states with the masses under the $K K ˉ$ thresholds requires the renormalization of the masses!
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); Nuclear Theory (nucl-th)
arXiv:
1709.02068 [pdf]
PRD(2017)·7 citations
06
[Submitted on 7 Sept 2017] (cross-list from hep-ph)
Light Pseudoscalar Mesons: an Inverse Instantaneous Bethe-Salpeter Glimpse
Wolfgang Lucha🇦🇹 · Franz F. Schoberl🇦🇹
Achieving self-consistent simultaneous interpretations of pions and kaons as bound states of quark and antiquark and as the (almost) massless boson states related, according to Goldstone's theorem, to the dynamical (and explicit) breakdown of the chiral symmetries of QCD still represents a major challenge. Applying inversion techniques to conveniently simplified versions of the homogeneous Bethe-Salpeter equation, governing bound states in quantum field theory, enables us to get along a straightforward route a qualitative idea of how the underlying effective interaction might look like.
Comments:
4 pages, 4 figures, contributed to "The European Physical Society Conference on High Energy Physics - EPS-HEP 2017" (5 - 12 July 2017, Venice, Italy)
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
1709.02130 [pdf]
PoS(2017)·1 citation
07
[Submitted on 7 Sept 2017] (cross-list from hep-ph)
Decay Constants of the Heavy-Light Mesons $D^{(*)}$ and $B^{(*)}$ : Isospin Breaking
Wolfgang Lucha🇦🇹 · Dmitri Melikhov🇦🇹 · Silvano Simula🇮🇹
QCD sum rules are analytic predictions of hadron observables from quantum chromodynamics. In the so-called local-duality limit of their Borel-transformed form, all nonperturbative contributions are encompassed by just a single quantity, an effective threshold beyond which, by assumption, all hadronic contributions are reliably described by perturbative QCD. Reconstructing its quark-mass dependence enables us to investigate the differences of the leptonic decay constants of heavy-light mesons effectuated by the tiny isospin-violating discrepancy of the masses of up and down quarks. By and large, our findings enjoy excellent agreement with the outcomes of earlier studies, the only exception being a lattice-QCD prediction for the $B$ mesons, where we find dramatic disagreement.
Comments:
4 pages, 1 figure, contributed to "The European Physical Society Conference on High Energy Physics - EPS-HEP 2017" (5 - 12 July 2017, Venice, Italy)
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Lattice (hep-lat); Nuclear Theory (nucl-th)
arXiv:
1709.02131 [pdf]
PoS(2017)·4 citations
08
[Submitted on 7 Sept 2017] (cross-list from hep-ph)
Collisional and thermal dissociation of $J / ψ$ and $Υ$ states at the LHC
Samuel Aronson🇺🇸 · Evan Borras🇺🇸 · Brunel Odegard🇺🇸 · Rishi Sharma🇮🇳 · Ivan Vitev🇺🇸
We present new results for the suppression of high transverse momentum charmonium [ $J / ψ, ψ (2 S)$ ] and bottomonium [ $Υ (1 S), Υ (2 S), Υ (3 S)$ ] states in Pb+Pb collisions at the Large Hadron Collider. Our theoretical formalism combines the collisional dissociation of quarkonia, as they propagate in the quark-gluon plasma, with the thermal wavefunction effects due to the screening of the $Q Q ˉ$ attractive potential in the medium. We find that a good description of the relative suppression of the ground and higher excited quarkonium states, transverse momentum and centrality distributions is achieved, when comparison to measurements at a center-of-mass energy of 2.76 TeV is performed. Theoretical predictions for the highest Pb+Pb center-of-mass energy of 5.02 TeV at the LHC, where new experimental results are being finalized, are also presented.
Comments:
8 pages, 8 eps figures; 2 figures and references added, introduction restructured; version to appear in PLB
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
1709.02372 [pdf]
PLB(2018)·63 citations

Affiliations

first authorsco-authorsvia INSPIRE