Nuclear Theory·nucl-th

Monday·January 25, 2016

4 papers—1 primary·3 cross-listed

01
[Submitted on 22 Jan 2016]
Effect of cluster-shell competition of $^{12}$ C on $E 0$ transitions in $^{16}$ O
H. Matsuno · N. Itagaki
In $^{16}$ O, we investigate the relation between the $E 0$ monopole transition matrix elements and cluster-shell competition using antisymmetrized quasi cluster model (AQCM), where the dissolution of $a l p ha$ clusters into quasi clusters due to the effect of the spin-orbit force is introduced. We focus on the structure change when the strength of the spin-orbit force is varied. The ground state dominantly has a compact four $a l p ha$ structure (doubly magic structure of the $p$ shell), which is rather independent of the strength. However the first excited state ( $0_{2}^{+}$ ) has $^{12}$ C $+ a l p ha$ cluster structure and this state is largely affected by the increase of the strength; the subclosure configuration of the $p_{3/2}$ shell for the $^{12}$ C cluster part becomes more important than three $a l p ha$ configuration. The $E 0$ transition from the ground state with compact four $a l p ha$ configuration to the $0_{2}^{+}$ state with $^{12}$ C $+ a l p ha$ cluster configuration is suppressed when increasing the spin-orbit strength. Although the $E 0$ operator itself does not have the spin dependence, the matrix element is sensitive to the difference of intrinsic spin structures of the two states. The $E 0$ transition characterizes the persistence of four $a l p ha$ structure in the $0_{2}^{+}$ state.
Subjects:
Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
arXiv:
1601.05892 [pdf]
1 citation
02
[Submitted on 22 Jan 2016] (cross-list from math.HO)
Much ado about Zero
Asis Kumar Chaudhuri
A brief historical introduction for the enigmatic number Zero is given. The discussions are for popular consumption.
Comments:
minor corrections are made. 13 pages, 5 figures
Subjects:
math.HO (math.HO); High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th); physics.pop-ph (physics.pop-ph)
arXiv:
1601.05983 [pdf]
0 citations
03
[Submitted on 22 Jan 2016] (cross-list from nucl-ex)
Scaling properties of the mean multiplicity and pseudorapidity density in $e^{-} + e^{+}$ , $e^{\pm}$ +p, p( $p ˉ$ )+p, p+A and A+A(B) collisions
Roy A. Lacey (1,2)🇺🇸 · Peifeng Liu (2)🇺🇸 · Niseem Magdy (1)🇺🇸 · M.Csanád (1,3)🇺🇸 · B. Schweid (2)🇺🇸 · N. N. Ajitanand (1)🇺🇸 · J. Alexander (1)🇺🇸 · R. Pak (4) ((1) Department of Chemistry, Stony Brook University, Stony Brook, NY, USA (2) Dept. of Physics, Stony Brook University, Stony Brook, NY, USA (3) Eotvos University, Department of Atomic Physics, Budapest, Hungary (4) Brookhaven National Laboratory, Upton, New York, USA)🇺🇸
The pseudorapidity density (dN/deta) for p+p, p+A and A+A(B) collisions, and the mean multiplicity <Nch> for ee, ep, and p+p collisions, are studied for an inclusive range of beam energies (Root_s). Characteristic scaling patterns are observed for both dN/deta and <Nch>, consistent with a thermal particle production mechanism for the bulk of the soft particles produced in all of these systems. They also validate an essential role for quark participants in these collisions. The scaled values for dN/deta and <Nch> are observed to factorize into contributions which depend on log(Root_s) and the number of nucleon or quark participant pairs (Npp). Quantification of these contributions give expressions which serve to systematize dN/deta and <Nch> measurements spanning nearly four orders of magnitude in Root_s, and to predict their values as a function of Root_s and Npp.
Comments:
5 pages 4 figures, submitted for publication
Subjects:
Nuclear Experiment (nucl-ex); High Energy Physics — Experiment (hep-ex); High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
1601.06001 [pdf]
Universe(2018)·36 citations
04
[Submitted on 22 Jan 2016] (cross-list from astro-ph.HE)
Fast spinning strange stars: possible ways to constrain interacting quark matter parameters
Sudip Bhattacharyya (TIFR, India)🇮🇳 · Ignazio Bombaci (Universita di Pisa / INFN / EGO, Italy)🇮🇹 · Domenico Logoteta (INFN, Italy)🇮🇹 · Arun V. Thampan (St. Joseph's College / IUCAA, India)🇮🇳
For a set of equation of state (EoS) models involving interacting strange quark matter, characterized by an effective bag constant (B_eff) and a perturbative QCD corrections term (a_4), we construct fully general relativistic equilibrium sequences of rapidly spinning strange stars for the first time. Computation of such sequences is important to study millisecond pulsars and other fast spinning compact stars. Our EoS models can support a gravitational mass (M_G) and a spin frequency at least up to approximately 3.0 solar mass and approximately 1250 Hz respectively, and hence are fully consistent with measured M_G and spin frequency values. This paper reports the effects of B_eff and a_4 on measurable compact star properties, which could be useful to find possible ways to constrain these fundamental quark matter parameters, within the ambit of our EoS models. We confirm that a lower B_eff allows a higher mass. Besides, for known M_G and spin frequency, measurable parameters, such as stellar radius, radius-to-mass ratio and moment of inertia, increase with the decrease of B_eff. Our calculations also show that a_4 significantly affects the stellar rest mass and the total stellar binding energy. As a result, a_4 can have signatures in evolutions of both accreting and non-accreting compact stars, and the observed distribution of stellar mass and spin and other source parameters. Finally, we compute the parameter values of two important pulsars, PSR J1614-2230 and PSR J1748-2446ad, which may have implications to probe their evolutionary histories, and for constraining EoS models.
Comments:
17 pages, 11 figures, 7 tables, accepted for publication in Monthly Notices of the Royal Astronomical Society
Subjects:
High Energy Astrophysical Phenomena (astro-ph.HE); Solar and Stellar Astrophysics (astro-ph.SR); General Relativity and Quantum Cosmology (gr-qc); Nuclear Theory (nucl-th)
arXiv:
1601.06120 [pdf]
MNRAS(2016)·53 citations

Affiliations

first authorsco-authorsvia INSPIRE

Effect of cluster-shell competition of 12C on E0 transitions in 16O

Much ado about Zero

Scaling properties of the mean multiplicity and pseudorapidity density in e−+e+, e±+p, p(pˉ​)+p, p+A and A+A(B) collisions

Fast spinning strange stars: possible ways to constrain interacting quark matter parameters

Affiliations

Effect of cluster-shell competition of $^{12}$ C on $E 0$ transitions in $^{16}$ O

Scaling properties of the mean multiplicity and pseudorapidity density in $e^{-} + e^{+}$ , $e^{\pm}$ +p, p( $p ˉ$ )+p, p+A and A+A(B) collisions