Tue·Jan 12, 2016Tuesday·January 12, 2016

1. 01*

   Beam Energy Dependence of the Third Harmonic of Azimuthal Correlations in Au+Au Collisions at RHIC

   STAR Collaboration: L. Adamczyk · J. K. Adkins · G. Agakishiev · M. M. Aggarwal · Z. Ahammed · I. Alekseev · A. Aparin · D. Arkhipkin · E. C. Aschenauer · A. Attri · G. S. Averichev · X. Bai and 326 other authors

   We present results from a harmonic decomposition of two-particle azimuthal correlations measured with the STAR detector in Au+Au collisions for energies ranging from $\sqrt{s_{NN}}=7.7$ GeV to 200 GeV. The third harmonic $v_3^2\{2\}=⟨\cos 3({\varphi }_1-{\varphi }_2)⟩$, where ${\varphi }_1-{\varphi }_2$ is the angular difference in azimuth, is studied as a function of the pseudorapidity difference between particle pairs $\Delta \eta ={\eta }_1-{\eta }_2$. Non-zero {\vthree} is directly related to the previously observed large-$\Delta \eta$ narrow-$\Delta \varphi$ ridge correlations and has been shown in models to be sensitive to the existence of a low viscosity Quark Gluon Plasma (QGP) phase. For sufficiently central collisions, $v_3^2\{2\}$ persist down to an energy of 7.7 GeV suggesting that QGP may be created even in these low energy collisions. In peripheral collisions at these low energies however, $v_3^2\{2\}$ is consistent with zero. When scaled by pseudorapidity density of charged particle multiplicity per participating nucleon pair, $v_3^2\{2\}$ for central collisions shows a minimum near {\snn}$=20$ GeV.

   nucl-exPRL(2016)·86 citations
2. 02*

   Measurement of inclusive jet production and nuclear modifications in pPb collisions at sqrt(s[NN]) = 5.02 TeV

   CMS Collaboration

   Inclusive jet production in pPb collisions at a nucleon-nucleon (NN) center-of-mass energy of sqrt(s[NN]) = 5.02 TeV is studied with the CMS detector at the LHC. A data sample corresponding to an integrated luminosity of 35 inverse nanobarns is analyzed. The jet transverse momentum spectra are studied in seven pseudorapidity intervals covering the range -2.0 < eta[CM] < 1.5 in the NN center-of-mass frame. The jet production yields at forward and backward pseudorapidity are compared and no significant asymmetry about eta[CM] = 0 is observed in the measured kinematic range. The measurements in the pPb system are compared to reference jet spectra obtained by extrapolation from previous measurements in pp collisions at sqrt(s) = 7 TeV. In all pseudorapidity ranges, nuclear modifications in inclusive jet production are found to be small, as predicted by next-to-leading order perturbative QCD calculations that incorporate nuclear effects in the parton distribution functions.

   nucl-exhep-exEPJC(2016)·86 citations
3. 03*

   Precision X-ray spectroscopy of kaonic atoms as a probe of low-energy kaon-nucleus interaction

   H. Shi🇮🇹 · M. Bazzi🇮🇹 · G. Beer🇨🇦 · G. Bellotti🇮🇹 · C. Berucci🇦🇹 · A. M. Bragadireanu🇷🇴 · D. Bosnar🇭🇷 · M. Cargnelli🇦🇹 · C. Curceanu🇮🇹 · A. D. Butt🇮🇹 · A. d'Uffizi🇮🇹 · C. Fiorini🇮🇹 and 20 other authors

   In the exotic atoms where one atomic $1s$ electron is replaced by a $K^{-}$, the strong interaction between the $K^{-}$ and the nucleus introduces an energy shift and broadening of the low-lying kaonic atomic levels which are determined by only the electromagnetic interaction. By performing X-ray spectroscopy for Z=1,2 kaonic atoms, the SIDDHARTA experiment determined with high precision the shift and width for the $1s$ state of $K^{-}p$ and the $2p$ state of kaonic helium-3 and kaonic helium-4. These results provided unique information of the kaon-nucleus interaction in the low energy limit.

   nucl-exEPJ Web Conf.(2016)·5 citations
4. 04*

   Model-independent determination of the astrophysical S-factor in laser-induced fusion plasmas

   D. Lattuada🇮🇹 · M. Barbarino · A. Bonasera🇺🇸 · W. Bang · H. J. Quevedo · M. Warren · F. Consoli · R. De Angelis🇮🇹 · P. Andreoli · S. Kimura🇯🇵 · G. Dyer · A. C. Bernstein and 7 other authors

   In this work, we present a new and general method for measuring the astrophysical S-factor of nuclear reactions in laser-induced plasmas and we apply it to d(d,n)${}^3$He. The experiment was performed with the Texas Petawatt laser, which delivered 150-270 fs pulses of energy ranging from 90 to 180 J to D${}_2$ or CD${}_4$ molecular clusters. After removing the background noise, we used the measured time-of-flight data of energetic deuterium ions to obtain their energy distribution. We derive the S-factor using the measured energy distribution of the ions, the measured volume of the fusion plasma and the measured fusion yields. This method is model-independent in the sense that no assumption on the state of the system is required, but it requires an accurate measurement of the ion energy distribution especially at high energies and of the relevant fusion yields. In the d(d,n)${}^3$He and ${}^3$He(d,p)${}^4$He cases discussed here, it is very important to apply the background subtraction for the energetic ions and to measure the fusion yields with high precision. While the available data on both ion distribution and fusion yields allow us to determine with good precision the S-factor in the d+d case (lower Gamow energies), for the d+${}^3$He case the data are not precise enough to obtain the S-factor using this method. Our results agree with other experiments within the experimental error, even though smaller values of the S-factor were obtained. This might be due to the plasma environment differing from the beam target conditions in a conventional accelerator experiment.

   nucl-exphysics.plasm-phPRC(2016)·18 citations
5. 05*

   Nucleon Resonance Structure Studies Via Exclusive KY Electroproduction

   Daniel S. Carman (for the CLAS Collaboration)🇺🇸

   Studying the structure of excited nucleon states employing the electroproduction of exclusive reactions is an important avenue for exploring the nature of the non-perturbative strong interaction. The electrocouplings of $N^{\ast }$ states in the mass range below 1.8~GeV have been determined from analyses of CLAS $\pi N$, $\eta N$, and $\pi \pi N$ data. This work has made it clear that consistent results from independent analyses of several exclusive channels with different couplings and non-resonant backgrounds but the same $N^{\ast }$ electro-excitation amplitudes, is essential to have confidence in the extracted results. In terms of hadronic coupling, many high-lying $N^{\ast }$ states preferentially decay through the $\pi \pi N$ channel instead of $\pi N$. Data from the $KY$ channels will therefore be critical to provide an independent analysis to compare the extracted electrocouplings for the high-lying $N^{\ast }$ states against those determined from the $\pi N$ and $\pi \pi N$ channels. A program to study excited $N^{\ast }$ state structure in both non-strange and strange exclusive electroproduction channels using CLAS12 will measure differential cross sections and polarization observables to be used as input to extract the ${\gamma }_{v}N{N}^{\ast }$ electrocoupling amplitudes for the most prominent $N^{\ast }$ states in the range of invariant energy $W$ up 3~GeV in the virtually unexplored domain of momentum transfers $Q^2$ up to 12~GeV${}^2$.

   nucl-exnucl-thFew Body Syst.(2016)·10 citations
6. 06*

   The hidden-charm pentaquark and tetraquark states

   Hua-Xing Chen🇨🇳 · Wei Chen🇨🇦 · Xiang Liu🇨🇳 · Shi-Lin Zhu🇨🇳

   In the past decade many charmonium-like states were observed experimentally. Especially those charged charmonium-like $Z_c$ states and bottomonium-like $Z_b$ states can not be accommodated within the naive quark model. These charged $Z_c$ states are good candidates of either the hidden-charm tetraquark states or molecules composed of a pair of charmed mesons. Recently, the LHCb Collaboration discovered two hidden-charm pentaquark states, which are also beyond the quark model. In this work, we review the current experimental progress and investigate various theoretical interpretations of these candidates of the multiquark states. We list the puzzles and theoretical challenges of these models when confronted with the experimental data. We also discuss possible future measurements which may distinguish the theoretical schemes on the underlying structures of the hidden-charm multiquark states.

   ↳ hep-phhep-exhep-latnucl-ex+1Phys.Rept.(2016)·1460 citations
7. 07*

   Cigar-shaped quarkonia under strong magnetic field

   Kei Suzuki🇯🇵 · Tetsuya Yoshida🇯🇵

   Heavy quarkonia in a homogeneous magnetic field are analyzed by using a potential model with constituent quarks. To obtain anisotropic wave functions and corresponding eigenvalues, the cylindrical Gaussian expansion method is applied, where the anisotropic wave functions are expanded by a Gaussian basis in the cylindrical coordinates. Deformation of the wave functions and the mass shifts of the $S$-wave heavy quarkonia (${\eta }_c$, $J/\psi$, ${\eta }_c(2S)$, $\psi (2S)$ and bottomonia) are examined for the wide range of external magnetic field. The spatial structure of the wave functions changes drastically as adjacent energy levels cross each other. Possible observables in heavy-ion collision experiments and future lattice QCD simulations are also discussed.

   ↳ hep-phhep-latnucl-exnucl-thPRD(2016)·32 citations
8. 08*

   Hydrodynamic fluctuations and dissipation in an integrated dynamical model

   Koichi Murase🇯🇵 · Tetsufumi Hirano🇯🇵

   We develop a new integrated dynamical model to investigate the effects of the hydrodynamic fluctuations on observables in high-energy nuclear collisions. We implement hydrodynamic fluctuations in a fully 3-D dynamical model consisting of the hydrodynamic initialization models of the Monte-Carlo Kharzeev-Levin-Nardi model, causal dissipative hydrodynamics and the subsequent hadronic cascades. By analyzing the hadron distributions obtained by massive event-by-event simulations with both of hydrodynamic fluctuations and initial-state fluctuations, we discuss the effects of hydrodynamic fluctuations on the flow harmonics, $v_n$ and their fluctuations.

   ↳ nucl-thhep-phnucl-exNPA(2016)·52 citations
9. 09*

   Establishing mass spectrum of $S=-1$ hyperon resonances via a dynamical coupled-channels analysis of $K^{-}p$ reactions

   Hiroyuki Kamano🇯🇵

   We report our recent effort for the extraction of resonance parameters (complex pole mass and residues etc.) associated with Lambda* and Sigma* hyperons. This was accomplished via a comprehensive partial-wave analysis of the data for K^- p --> barK N, pi Sigma, pi Lambda, eta Lambda, K Xi reactions from the thresholds up to W=2.1 GeV within a dynamical coupled-channels approach. The results suggest a possible existence of new narrow J^P=3/2^+ \Lambda resonance with pole mass 1671^{+2}_{-8} -i(5^{+11}_{-2}) MeV, located close to the eta Lambda threshold. This resonance is found to be responsible for reproducing the data for K^-p --> eta Lambda differential cross sections near the threshold, and thus the data seem favor its existence. The extracted poles for J^P=1/2^- Lambda resonances below the barK N threshold, including Lambda(1405), are also presented.

   ↳ nucl-thhep-phnucl-exJPS Conf.Proc.(2017)·0 citations

* Reconstructed cohort: no mailing for this day survives in the archive. Papers are grouped by their submission times and arXiv's announcement cut-off, assuming announcement without delay; positions follow identifier order. Validated at ~91% exact-day agreement against the archived era.