Nuclear Theory·nucl-th

Tuesday·September 20, 2016

13 papers—9 primary·4 cross-listed

01
[Submitted on 17 Sept 2016]
Centrality dependence of chemical freeze-out parameters from net-proton and net-charge fluctuations using hadron resonance gas model
Rama Prasad Adak🇮🇳 · Supriya Das🇮🇳 · Sanjay K. Ghosh🇮🇳 · Rajarshi Ray🇮🇳 · Subhasis Samanta🇮🇳
We estimate chemical freeze-out parameters in HRG and EVHRG model by fitting the experimental information of net-proton and net-charge fluctuations measured in Au + Au collisions by the STAR collaboration at RHIC. We observe that chemical freeze-out parameters obtained from lower and higher order fluctuations are though almost same for $s_{N N} > 27$ GeV, tend to deviate from each other at lower $s_{N N}$ . Moreover, these separations increase with decrease of $s_{N N}$ and for a fixed $s_{N N}$ increase towards central collisions. Furthermore, we observe an approximate scaling behaviour of $(μ_{B} / T) / (μ_{B} / T)_{ce n t r a l}$ with $(N_{p a r t}) / (N_{p a r t})_{ce n t r a l}$ for the parameters estimated from lower order fluctuations for 11.5 GeV $\leq s_{N N} \leq$ 200 GeV. Scaling is violated for the parameters estimated from higher order fluctuations for $s_{N N} = 11.5$ and 19.6 GeV. It is observed that the chemical freeze-out parameter, which can describe $σ^{2} / M$ of net-proton very well in all energies and centralities, can not describe the $s σ$ equally well and vice versa.
Comments:
11 pages, 6 figures
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex)
arXiv:
1609.05318 [pdf]
PRC(2017)·24 citations
02
[Submitted on 18 Sept 2016]
Predictions on the alpha decay chains of superheavy nuclei with Z =121 within the range 290 $\leq$ A $\leq$ 339
K. P. Santhosh · C. Nithya
A systematic study on the alpha decay half lives of various isotopes of superheavy element \textit{Z} = 121 within the range 290 $\leq$ A $\leq$ 339 is presented for the first time using Coulomb and proximity potential model for deformed nuclei (CPPMDN). The calculated $α$ decay half lives of the isotopes within our formalism match well with the values computed using Viola-Seaborg systematic, Universal curve of Poenaru et al., and the analytical formula of Royer. In our study by comparing the $α$ decay half lives with the spontaneous fission half lives, we have predicted $2 α$ chain from $^{309, 311, 312}$ 121, $3 α$ chain from $^{310}$ 121 and $1 α$ chain from $^{313, 314}$ 121. Clearly our study shows that the isotopes of superheavy element \textit{Z} = 121 within the mass range 309 $\leq$ A $\leq$ 314 will survive fission and can be synthesized and detected in the laboratory via alpha decay. We hope that our predictions will provide a new guide to future experiments.
Comments:
16 pages, 6 figures. arXiv admin note: text overlap with arXiv:1604.00296, arXiv:1504.00872
Subjects:
Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
arXiv:
1609.05495 [pdf]
IJMPE(2016)·8 citations
03
[Submitted on 18 Sept 2016]
Feasibility of observing the {\alpha} decay chains from isotopes of SHN with Z = 128, Z = 126, Z = 124 and Z = 122
K. P. Santhosh · B. Priyanka · C. Nithya
Taking the Coulomb and proximity potential model for deformed nuclei (CPPMDN) as the interacting potential for the post-scission region, the alpha decay properties of 34 isotopes of the superheavy nuclei with Z = 128 within the range 306 $\leq$ A $\leq$ 339 have been studied, considering both the parent and daughter nuclei to be deformed. The manuscript also deals with the decay properties of the isotopes of Z = 126 (within 288 $\leq$ A $\leq$ 339), Z = 124 (within 284 $\leq$ A $\leq$ 339) and Z = 122 (within 280 $\leq$ A $\leq$ 339). The alpha decay half lives thus evaluated has been compared with the values evaluated using other theoretical models and it was seen that, our theoretical alpha decay half lives matches well with these values. Through the present study, we have underlined and have established the fact that, among the 192 isotopes considered in the present study, only those isotopes $^{321 - 324, 328 - 335}$ 128, $^{318 - 320, 323 - 327}$ 126, $^{305 - 308, 315 - 322}$ 124 and $^{298 - 307, 311 - 314}$ 122 can be synthesized and detected through alpha decay in laboratory. As the alpha decay half lives of these superheavy isotopes lie within the experimental limits, we hope these predictions, on the decay modes of these unknown nuclei, to pave the way for the future experiments. The proton separation energy calculations on $^{306 - 339}$ 128, $^{288 - 336}$ 126, $^{284 - 339}$ 124 and $^{280 - 339}$ 122 superheavy nuclei have also been done and the study revealed the probable proton emitters among these nuclei.
Comments:
37 pages, 13 figures. arXiv admin note: text overlap with arXiv:1604.00296, arXiv:1504.00872
Subjects:
Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
arXiv:
1609.05498 [pdf]
NPA(2016)·26 citations
04
[Submitted on 19 Sept 2016]
Proton-proton hollowness at the LHC from inverse scattering
Enrique Ruiz Arriola🇪🇸 · Wojciech Broniowski🇵🇱
Parameterizations of the pp scattering data at the LHC collision energies indicate a hollow in the inelasticity profile of the pp interaction, with less absorption for head-on collisions than at a non-zero impact parameter. We show that some qualitatively unnoticed features may be unveiled by a judicious application of the inverse scattering problem in the eikonal approximation and interpre- tation within an optical potential model. The hollowness effect is magnifed in a 3D picture of the optical potential, and will presumably be enhanced at yet higher energies. Moreover, in 3D it sets in at much smaller energies than at the LHC. We argue that hollowness in the impact parameter is a quantum effect, relying on the build-up of the real part of the eikonal scattering phase and its possible passage through $π /2$ . We also show that it precludes models of inelastic collisions where inelasticity is obtained by naive folding of partonic densities.
Comments:
9 pages, 6 figures,expanded version with further discussions
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Experiment (hep-ex); High Energy Physics — Phenomenology (hep-ph)
arXiv:
1609.05597 [pdf]
PRD(2017)·29 citations
05
[Submitted on 19 Sept 2016]
Photoproduction of $π^{0}$ -Mesons on the Nucleon and Deuteron
Eed M. Darwish🇸🇦 · A. Hemmdan🇪🇬 · N. T. El-Shamy🇪🇬
The photoproduction of $π^{0}$ -mesons from the nucleon and deuteron has been studied for incidents of photon energies up to 1.5 GeV. By using the MAID-2007 model for the process on the nucleon, we predict results for the unpolarized and helicity-dependent total cross sections of the semi-exclusive reaction $γ d \to π^{0} X$ ( $X = n p + d$ ) with the inclusion of rescattering effects. We find that rescattering effects yield a substantially large contribution. The extracted results are compared with the available experimental data and a satisfactory agreement is obtained. In addition, the contribution of $γ d \to π^{0} X$ ( $X = n p + d$ ) to the finite GDH integral has been evaluated by explicit integration up to 1.5 GeV and a total value of 256.96 $μ$ b has been obtained. Convergence of the GDH integral has been reached.
Comments:
Mini Review, 6 Pages, 6 Figures, 1 Table
Subjects:
Nuclear Theory (nucl-th)
arXiv:
1609.05628 [pdf]
Makara J.Sci.(2016)·3 citations
06
[Submitted on 19 Sept 2016]
Nuclear structure calculations for two-neutrino double-beta decay
P. Sarriguren · O. Moreno · E. Moya de Guerra
We study the two-neutrino double-beta decay in 76Ge, 116Cd, 128Te, 130Te, and 150Nd, as well as the two Gamow-Teller branches that connect the double-beta decay partners with the states in the intermediate nuclei. We use a theoretical microscopic approach based on a deformed selfconsistent mean field with Skyrme interactions including pairing and spin-isospin residual forces, which are treated in a proton-neutron quasiparticle random-phase approximation. We compare our results for Gamow-Teller strength distributions with experimental information obtained from charge-exchange reactions. We also compare our results for the two-neutrino double-beta decay nuclear matrix elements with those extracted from the measured half-lives. Both single-state and low-lying-state dominance hypotheses are analyzed theoretically and experimentally making use of recent data from charge-exchange reactions and beta decay of the intermediate nuclei.
Comments:
11 pages, 6 figures. arXiv admin note: text overlap with arXiv:1502.05889
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph)
arXiv:
1609.05648 [pdf]
Adv.High Energy Phys.(2016)·6 citations
07
[Submitted on 19 Sept 2016]
Heavy quark dynamics in QCD matter
Santosh K. Das🇮🇹 · Francesco Scardina🇮🇹 · Salvatore Plumari🇮🇹 · Vincenzo Greco🇮🇹
Simultaneous description of heavy quark nuclear suppression factor $R_{AA}$ and the elliptic flow $v_{2}$ is a top challenge for all the existing models. We highlight how the temperature dependence of the energy loss/transport coefficients is responsible to address a large part of such a puzzle along with the the full solution of the Boltzmann collision integral for the momentum evolution of heavy quark. We consider four different models to evaluate the temperature dependence of drag coefficients of the heavy quark in the QGP. We have also highlighted the heavy quark dynamics in the presence of an external electromagnetic field which develops a sizable heavy quark directed flow, $v_{1} (y)$ , can be measurable at LHC.
Comments:
4 pages, To appear in the proceedings of SQM-2016
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph)
arXiv:
1609.05751 [pdf]
J.Phys.Conf.Ser.(2017)·1 citation
08
[Submitted on 19 Sept 2016]
Some aspects on four quarks recombination
G. Toledo Sanchez🇲🇽 · I. A. Toledano Juarez🇲🇽
We have performed a 3-D Monte Carlo simulation of a system composed of two identical light quarks ( $q q$ ) and two identical antiquarks ( $Q ˉ Q ˉ$ ) and determined whether it is energetically more favorable to form a tetraquark or two mesons, as a function of the interparticle separation distance which, for a fixed number of particles, can be identified as a particle density. In this proceedings, we highlight the main results and elaborate on the implications in properties like the correlation function for two-mesons and characterize the isolated diquark correlation function. We analize the four-body potential evolution and exhibit its linear behavior as a function of the invariant distance. We track the dynamical flipping among configurations to determine the recombination probability, exhibiting the importance of the tetraquark state.
Comments:
To be published in Journal of Physics Conference Series (IOP). Joint Proceedings of the XV Mexican Workshop on Particles and Fields & the XXX Annual Meeting of the Division of Particles and Fields of the Mexican Physical Society
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph)
arXiv:
1609.05753 [pdf]
J.Phys.Conf.Ser.(2016)·0 citations
09
[Submitted on 15 Sept 2016]
The physics mechanisms of light and heavy flavor $v_{2}$ and mass ordering in AMPT
Hanlin Li🇨🇳 · Zi-Wei Lin🇨🇳 · Fuqiang Wang🇺🇸
A Multi-Phase Transport (AMPT) model has been shown to describe experimental data well, such as the bulk properties of particle spectra and elliptic anisotropy ( $v_{2}$ ) in heavy ion collisions. Recent studies have shown that AMPT describes the $v_{2}$ data in small system collisions as well. In these proceedings, we first investigate the origin of the mass ordering of identified hadrons $v_{2}$ in heavy ion as well as small system collisions. We then study the production mechanism of the charm $v_{2}$ in light of the escape mechanism for the light quark $v_{2}$ .
Comments:
SQM2016 proceeding, 4 pages, 4 figures
Subjects:
Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
arXiv:
1609.05862 [pdf]
J.Phys.Conf.Ser.(2017)·2 citations
10
[Submitted on 18 Sept 2016] (cross-list from hep-ph)
Theory of hard probes in PbPb collisions
Yang-Ting Chien🇺🇸
The jet quenching phenomenon in heavy ion collisions provides a strong evidence of the modification of parton shower in the quark-gluon plasma. This contribution focuses on the hard probes of QGP using jets and summarizes the new theoretical progress of jet substructure modification studies using effective field theory techniques. We emphasize the important role of jet substructure observables as they probe various aspects of the jet formation mechanism and allow us to study the medium properties in great details. The precise calculations require the systematic resummation and consistently including medium modifications. Specifically, we discuss the calculations of jet shapes and cross sections in proton-proton and lead-lead collisions at the LHC using soft-collinear effective theory, with Glauber gluon interactions in the medium. In the end we present the comparison between our calculations and the recent measurements at the LHC with very good agreement. We conclude that precise jet modification studies in heavy ion collisions has been initiated.
Comments:
10 pages, 8 figures. Talk presented at Fourth Annual Large Hadron Collider Physics conference (LHCP2016), 13-18 June 2016, Lund, Sweden
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
1609.05441 [pdf]
PoS(2016)·0 citations
11
[Submitted on 19 Sept 2016] (cross-list from hep-ph)
Mini-Proceedings, 18th meeting of the Working Group on Radiative Corrections and MC Generators for Low Energies
H. Czyż · S. Eidelman · F. Ignatov · A. Keshavarzi · A. Kupsc · V. E. Lyubovitskij · P. Masjuan · A. Nyffeler · G. Pancheri · E. Tomasi-Gustafsson · G. Venanzoni
The mini-proceedings of the 18 $^{th}$ Meeting of the "Working Group on Radiative Corrections and MonteCarlo Generators for Low Energies" held in Frascati, 19 $^{th}$ - 20 $^{st}$ May, are presented. These meetings, started in 2006, have as aim to bring together experimentalists and theoreticians working in the fields of meson transition form factors, hadronic contributions to the anomalous magnetic moment of the leptons, and the effective fine structure constant. The development of MonteCarlo generators and Radiative Corrections for precision $e^{+} e^{-}$ and $τ$ -lepton physics are also covered, with emphasis on meson production. At this workshop, a documentary entitled {\it Bruno Touschek with AdA in Orsay} commemorating the first observation of electron-positron collisions in a laboratory was also presented. With this edition, the working group reaches 10 years of continuous activities.
Comments:
27 pages, 10 contributions. Editors: H. Czyz, P. Masjuan, and G. Venanzoni
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
1609.05651 [pdf]
0 citations
12
[Submitted on 19 Sept 2016] (cross-list from hep-ph)
Properties of vector mesons in four pseudoscalars electroproduction
G. Toledo Sanchez🇲🇽
Vector mesons and the $W$ gauge boson share some common features, such as the spin and a very short lifetime. The electromagnetic properties of the $W$ are linked to its gauge nature and thus a big effort has been devoted to measure them, while accounting for its instability. In this work, we elaborate on how these ideas can be translated to study vector mesons. We focus in the unstable property of such states and the restrictions from electromagnetic gauge invariance, describing the differences and similarities. Then, we describe the four pseudoscalars electroproduction as an analog to the $e^{+} e^{-} \to 4 f er mi o n s$ process, used to study the electromagnetic properties of the $W$ boson. We point out that the current experimental capabilities are reaching the possibility to measure the magnetic dipole moment of light vector mesons.
Comments:
To be published in Journal of Physics Conference Series (IOP). Joint Proceedings of the XV Mexican Workshop on Particles and Fields & the XXX Annual Meeting of the Division of Particles and Fields of the Mexican Physical Society
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
1609.05746 [pdf]
J.Phys.Conf.Ser.(2016)·0 citations
13
[Submitted on 19 Sept 2016] (cross-list from hep-ph)
Angular Structure of Jet Quenching Within a Hybrid Strong/Weak Coupling Model
Jorge Casalderrey-Solana🇬🇧 · Doga Gulhan🇨🇭 · Guilherme Milhano🇵🇹 · Daniel Pablos🇪🇸 · Krishna Rajagopal🇺🇸
Within the context of a hybrid strong/weak coupling model of jet quenching, we study the modification of the angular distribution of the energy within jets in heavy ion collisions, as partons within jet showers lose energy and get kicked as they traverse the strongly coupled plasma produced in the collision. To describe the dynamics transverse to the jet axis, we add the effects of transverse momentum broadening into our hybrid construction, introducing a parameter $K \equiv q^/ T^{3}$ that governs its magnitude. We show that, because of the quenching of the energy of partons within a jet, even when $K \neq = 0$ the jets that survive with some specified energy in the final state are narrower than jets with that energy in proton-proton collisions. For this reason, many standard observables are rather insensitive to $K$ . We propose a new differential jet shape ratio observable in which the effects of transverse momentum broadening are apparent. We also analyze the response of the medium to the passage of the jet through it, noting that the momentum lost by the jet appears as the momentum of a wake in the medium. After freezeout this wake becomes soft particles with a broad angular distribution but with net momentum in the jet direction. We show that the particles coming from the response of the medium to the momentum and energy deposited in it leads to a correlation between the momentum of soft particles well separated from the jet in angle with the direction of the jet momentum, and find qualitative but not quantitative agreement with experimental data on observables designed to extract such a correlation. By confronting the results that we obtain upon introducing transverse momentum broadening and the response of the medium to the jet with available jet data, we highlight the importance of these processes for understanding the internal, soft, angular structure of high energy jets.
Comments:
62 pages, 14 figures
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
1609.05842 [pdf]
JHEP(2017)·203 citations

Affiliations

first authorsco-authorsvia INSPIRE