Thu·Dec 4, 2014Thursday·December 4, 2014

1. 01*

   Measurement of the higher-order anisotropic flow coefficients for identified hadrons in Au$+$Au collisions at $\sqrt{s_{{}_{NN}}}$ = 200 GeV

   A. Adare · S. Afanasiev · C. Aidala · N.N. Ajitanand · Y. Akiba · H. Al-Bataineh · J. Alexander · K. Aoki · Y. Aramaki · E.T. Atomssa · R. Averbeck · T.C. Awes and 376 other authors

   New PHENIX measurements of the anisotropic flow coefficients $v_2\{{\Psi }_2\}$, $v_3\{{\Psi }_3\}$, $v_4\{{\Psi }_4\}$ and $v_4\{{\Psi }_2\}$ for identified particles (${\pi }^{\pm }$, $K^{\pm }$, and $p+\bar{p}$) obtained relative to the event planes ${\Psi }_n$ in Au$+$Au collisions at $\sqrt{s_{{}_{NN}}}$ = 200 GeV are presented as functions of collision centrality and particle transverse momenta $p_T$. The $v_n$ coefficients show characteristic patterns consistent with hydrodynamical expansion of the matter produced in the collisions. For each harmonic $n$, a modified valence quark number $n_q$ scaling plotting $v_n/(n_q{)}^{n/2}$ versus ${\mathrm{KE}}_T/n_q$ is observed to yield a single curve for all the measured particle species for a broad range of transverse kinetic energies ${\mathrm{KE}}_T$. A simultaneous blast wave model fit to the observed particle spectra and $v_n(p_T)$ coefficients identifies spatial eccentricities $s_n$ at freeze-out, which are much smaller than the initial-state geometric values.

   nucl-exPRC(2016)·80 citations
2. 02*

   Systematic Study of Azimuthal Anisotropy in Cu$+$Cu and Au$+$Au Collisions at $\sqrt{s_{{}_{NN}}}=62.4$ and 200 GeV

   A. Adare · S. Afanasiev · C. Aidala · N.N. Ajitanand · Y. Akiba · H. Al-Bataineh · A. Al-Jamel · J. Alexander · K. Aoki · L. Aphecetche · R. Armendariz · S.H. Aronson and 413 other authors

   We have studied the dependence of azimuthal anisotropy $v_2$ for inclusive and identified charged hadrons in Au$+$Au and Cu$+$Cu collisions on collision energy, species, and centrality. The values of $v_2$ as a function of transverse momentum $p_T$ and centrality in Au$+$Au collisions at $\sqrt{s_{{}_{NN}}}$=200 GeV and 62.4 GeV are the same within uncertainties. However, in Cu$+$Cu collisions we observe a decrease in $v_2$ values as the collision energy is reduced from 200 to 62.4 GeV. The decrease is larger in the more peripheral collisions. By examining both Au$+$Au and Cu$+$Cu collisions we find that $v_2$ depends both on eccentricity and the number of participants, $N_{\mathrm{part}}$. We observe that $v_2$ divided by eccentricity ($\epsilon$) monotonically increases with $N_{\mathrm{part}}$ and scales as $N_{\mathrm{part}}^{1/3}$. The Cu$+$Cu data at 62.4 GeV falls below the other scaled $v_2$ data. For identified hadrons, $v_2$ divided by the number of constituent quarks $n_q$ is independent of hadron species as a function of transverse kinetic energy $K{E}_T=m_T-m$ between $0.1<K{E}_T/n_q<1$ GeV. Combining all of the above scaling and normalizations, we observe a near-universal scaling, with the exception of the Cu$+$Cu data at 62.4 GeV, of $v_2/(n_q\cdot \epsilon \cdot N_{\mathrm{part}}^{1/3})$ vs $K{E}_T/n_q$ for all measured particles.

   nucl-exPRC(2015)·42 citations
3. 03*

   Physics potential of polarized positrons at the Jefferson Laboratory

   Eric Voutier🇫🇷

   Charge symmetry in hadronic reactions, either verified or violated, appears to be in some circumstances a mandatory guide for model-independent understanding of the structure and dynamics at play. The recent demonstration of the PEPPo concept for the production of polarized positrons opens new physics perspectives at the Jefferson Laboratory. Polarized positron beams, in complement to existing polarized electron beams, are shown to bring multi-Physics opportunities.

   nucl-exhep-exNucl.Theor.(2014)·12 citations
4. 04*

   Jefferson Lab Science, Past and Future

   R.D. McKeown🇺🇸

   The Continuous Electron Beam Accelerator Facility (CEBAF) and associated experimental equipment at Jefferson Lab comprise a unique facility for experimental nuclear physics. This facility is presently being upgraded, which will enable a new experimental program with substantial discovery potential to address important topics in nuclear, hadronic, and electroweak physics. Further in the future, it is envisioned that the Laboratory will evolve into an electron-ion colliding beam facility.

   nucl-exhep-exphysics.acc-phFew Body Syst.(2015)·0 citations
5. 05*

   An RF-only ion-funnel for extraction from high-pressure gases

   Thomas Brunner🇺🇸 · Daniel Fudenberg🇺🇸 · Victor Varentsov🇷🇺 · Amanda Sabourov🇺🇸 · Giorgio Gratta🇺🇸 · Jens Dilling🇨🇦 · Ralph DeVoe🇺🇸 · David Sinclair🇨🇦 · William Fairbank Jr.🇺🇸 · Joshua B Albert🇺🇸 · David J Auty🇺🇸 · Phil S Barbeau🇺🇸 and 65 other authors

   An RF ion-funnel technique has been developed to extract ions from a high-pressure (10 bar) noble-gas environment into vacuum ($10^{-6}$ mbar). Detailed simulations have been performed and a prototype has been developed for the purpose of extracting ${}^{136}$Ba ions from Xe gas with high efficiency. With this prototype, ions have been extracted for the first time from high-pressure xenon gas and argon gas. Systematic studies have been carried out and compared to the simulations. This demonstration of extraction of ions with mass comparable to that of the gas generating the high-pressure into vacuum has applications to Ba tagging from a Xe-gas time-projection chamber (TPC) for double beta decay as well as to the general problem of recovering trace amounts of an ionized element in a heavy (m$>40$ u) carrier gas.

   ↳ physics.ins-detnucl-exInt.J.Mass Spectrometry(2015)·37 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.