Tue·Jul 30, 2019Tuesday·July 30, 2019

1. 01*

   Exclusive ${\mathbf{\pi }}^0\mathbf{p}$ electroproduction off protons in the resonance region at photon virtualities 0.4~GeV${}^2$ $\le {\mathbf{Q}}^2\le 1$~GeV${}^2$

   N. Markov · K. Joo · V.D. Burkert · V.I. Mokeev · L. C. Smith · M. Ungaro · S. Adhikari · M.J.~Amaryan · G. Angelini · H.~Atac · H.~Avakian · C. Ayerbe Gayoso and 112 other authors

   The exclusive electroproduction process $ep\to e^{\prime }{p}^{\prime }{\pi }^0$ was measured in the range of photon virtualities $Q^2=0.4-1.0$~GeV${}^2$ and the invariant mass range of the $p{\pi }^0$ system of $W=1.1-1.8$~GeV. These kinematics are covered in exclusive ${\pi }^0$ electroproduction off the proton with nearly complete angular coverage in the $p{\pi }^0$ center-of-mass system and with high statistical accuracy. Nearly 36000 cross section points were measured, and the structure functions ${\sigma }_T+ϵ{\sigma }_L$, ${\sigma }_{LT}$, and ${\sigma }_{TT}$, were extracted via fitting the ${\varphi }_{{\pi }^0}$ dependence of the cross section. A Legendre polynomial expansion analysis demonstrates the sensitivity of our data to high-lying $N^{\ast }$ and ${\Delta }^{\ast }$ resonances with $M>1.6$ GeV. As part of a broad effort to determine the electrocouplings of the $N^{\ast }$ and ${\Delta }^{\ast }$ resonances using both single- and double-pion electroproduction, this dataset is crucial for the reliable extraction of the high-lying resonance electrocouplings from the combined isospin analysis of the $N\pi$ and ${\pi }^{+}{\pi }^{-}p$ channels.

   nucl-exPRC(2020)·20 citations
2. 02*

   Level scheme of ${}^{153}$Sm obtained from ${}^{152}$Sm($n_{th}$,$\gamma$) reaction using $\gamma -\gamma$ coincidence spectrometer

   Nguyen Ngoc Anh · Nguyen Quang Hung · Nguyen Xuan Hai · Pham Dinh Khang · A. M. Sukhovoj · L. V. Mitsyna · Ho Huu Thang · Le Hong Khiem

   The level scheme of the compound ${}^{153}$Sm nucleus formed via the ${}^{152}$Sm($n_{th}$,$\gamma$) reaction is studied by using the $\gamma -\gamma$ coincidence spectrometer at Dalat Nuclear Research Institute, Vietnam. All the gamma cascades, which correspond to the decays from the compound state to 12 final levels of 0 (${\frac{3}{2}}^{+}$), 7.535 (${\frac{5}{2}}^{+}$), 35.844 (${\frac{3}{2}}^{-}$), 90.875 (${\frac{5}{2}}^{-}$), 126.412 (${\frac{1}{2}}^{-}$), 127.298 (${\frac{3}{2}}^{-}$), 182.902 (${\frac{5}{2}}^{-}$), 321.113 (${\frac{3}{2}}^{+}$), 404.129 (${\frac{1}{2}}^{-}$), 405.470 (${\frac{3}{2}}^{-}$), 414.924 (${\frac{1}{2}}^{+}$), and 481.088 (${\frac{3}{2}}^{+}$) keV, have been measured. A total number of 386 cascades corresponding to 576 gamma transitions has been detected. Among these cascades, 103 primary gamma transitions together with their corresponding intermediate levels and 299 secondary transitions have been determined. In addition, 29 primary gamma transitions, 42 intermediate levels, and 8 secondary transitions have been found to be the same as those extracted from the ENSDF data. The remain 74 primary gamma transitions, 61 intermediate levels, and 291 secondary transitions are therefore considered as the new data. In particular, based on an assumption that most of the transitions are dipole, we have tentatively assigned the unique spin value of $\frac{3}{2}\hslash$ for 53 observed intermediate levels corresponding to the cascades from the compound state to the final ones of 7.535 (${\frac{5}{2}}^{+}$), 90.875 (${\frac{5}{2}}^{-}$), and 182.902 (${\frac{5}{2}}^{-}$) keV, whereas the remain levels are assigned with the spin values in the range of $[\frac{1}{2},\frac{3}{2}]\hslash$...

   nucl-exnucl-th0 citations
3. 03*

   Shape coexistence in the neutron-deficient lead region: A systematic study of lifetimes in the even-even ${}^{188-200}$Hg with GRIFFIN

   B. Olaizola🇨🇦 · A.B. Garnsworthy🇨🇦 · G.C. Ball🇨🇦 · N. Bernier🇨🇦 · M. Bowry🇺🇸 · R. Caballero-Folch🇨🇦 · I. Dillmann🇨🇦 · S. Georges · G. Hackman🇨🇦 · J. Smallcombe🇨🇦 · J. K. Smith · D. Southall and 28 other authors

   Lifetimes of $2_1^{+}$ and $4_1^{+}$ states, as well as some negative-parity and non-yrast states, in ${}^{188-200}$Hg were measured using $\gamma -\gamma$ electronic fast timing techniques with the LaBr${}_3$(Ce) detector array of the GRIFFIN spectrometer. The excited states were populated in the $ϵ/{\beta }^{+}$-decay of $J^{\pi }=7^{+}/2^{-}$ ${}^{188-200}$Tl produced at the TRIUMF-ISAC facility. The deduced B(E2) values are compared to different interacting boson model predictions. The precision achieved in this work over previous ones allows for a meaningful comparison with the different theoretical models of these transitional Hg isotopes, which confirms the onset of state mixing in ${}^{190}$Hg.

   nucl-exPRC(2019)·34 citations
4. 04*

   Coherent-Nuclear Pion Photoproduction and Neutron Radii

   Gerald A. Miller🇺🇸

   { {\bf Background:} Knowing the difference between the neutron and proton densities of nuclei is a significant topic because of its importance for understanding neutron star structures and cooling mechanisms. The coherent-nuclear photoproduction of pions, $(\text{g},{\pi }^0)$, combined with elastic electron scattering, has been suggested to be a very accurate probe of density differences. {\bf Purpose:} Study the $(\text{g},{\pi }^0)$ reaction mechanism so as to better access the uncertainties involved in extracting the neutron density. {\bf Methods:} Include the effects of final-state pion-nucleus charge-exchange reactions on the cross section and study the influence of the non-zero spatial extent of the proton. {\bf Results:} The effects of final-state charge-exchange increase the cross section between 6\% and 5\%, generally decreasing as the momentum transfer increases. This leads to an increase of the extracted neutron skin distance by about 50\%. The validity of the previous treatments of the proton size is confirmed. {\bf Conclusion:} The model dependence of the theoretically computed cross section increases the total systematic uncertainty (experiment plus theory) in extracting the neutron skin from the $(\text{g},{\pi }^0)$ cross section by at least a factor of three. }

   ↳ nucl-thhep-phnucl-exPRC(2019)·11 citations
5. 05*

   A global extraction of the jet transport coefficient in cold nuclear matter

   Peng Ru🇨🇳 · Zhong-Bo Kang🇺🇸 · Enke Wang🇨🇳 · Hongxi Xing🇨🇳 · Ben-Wei Zhang🇨🇳

   Within the framework of the generalized QCD factorization formalism, we perform the first global analysis of the jet transport coefficient ($\hat{q}$) for cold nuclear matter. The analysis takes into account the world data on transverse momentum broadening in semi-inclusive electron-nucleus deep inelastic scattering, Drell-Yan dilepton and heavy quarkonium production in proton-nucleus collisions, as well as the nuclear modification of the structure functions in deep inelastic scattering, comprising a total of 215 data points from 8 data sets. For the first time, we clarify quantitatively the universality and probing scale dependence of the nuclear medium property as encoded in $\hat{q}$. We expect that the determined parametrization of $\hat{q}$ in cold nuclear matter will have significant impact on precise identification of the transport property of hot dense medium created in heavy ion collisions.

   ↳ hep-phhep-exnucl-exnucl-thPRD(2021)·46 citations
6. 06*

   Smallest QCD Droplet and Multiparticle Correlations in pp Collisions

   Seyed Farid Taghavi🇩🇪

   The collective evolution of produced matter in heavy-ion collisions is effectively described by hydrodynamics from time scales greater than the inverse of the temperature, $\tau \gtrsim 1/T$. In the context of the Gubser solution, I show that the hydrodynamization condition $\tau T\gtrsim 1$ is translated into an allowed domain in the spatial system size and the final multiplicity for hydrodynamics applicability. It turns out that the flow measurements in pp collisions are inside the domain of validity. I predict that by approaching the boundaries of the allowed domain the hydrodynamic response to the initial ellipticity changes its sign. I follow a rather model-independent approach for the initial state where, instead of modeling the initial energy density of individual events, the initial system size and ellipticity event-by-event fluctuation are modeled. The model, initial state fluctuation+Gubser solution+Cooper-Frye freeze-out, describes the multiplicity and transverse momentum dependence of two-point and four-point correlation functions ($c_2\{2\}$ and $c_2\{4\}$) in an accurate agreement with pp collision experimental measurements. In particular, the sign of the four-point correlation function is the same as the observation, which failed to be described correctly in previous studies. I also predict a signal for the sign change in the hydrodynamic response that can be inspected in future experimental measurements of two-point and four-point correlation functions at lower multiplicities.

   ↳ nucl-thhep-phnucl-exPRC(2021)·11 citations
7. 07*

   Ruling out the supersoft high-density symmetry energy from the discovery of PSR J0740+6620 with mass $2.14_{-0.09}^{+0.10}{M}_{\odot }$

   Ying Zhou🇨🇳 · Lie-Wen Chen🇨🇳

   Using the very recently reported mass $2.14_{-0.09}^{+0.10}{M}_{\odot }$ of PSR J0740+6620 together with the data of finite nuclei and the constraints on the equation of state of symmetric nuclear matter at suprasaturation densities from flow data in heavy-ion collisions, we show that the symmetry energy $E_{\mathrm{sym}}(n)$ cannot be supersoft so that it becomes negative at suprasaturation densities in neutron stars (NSs) and thus may make the NS have a pure neutron matter core. This is in contrast to the fact that using the mass $2.01\pm 0.04M_{\odot }$ of PSR J0348+0432 as the NS maximum mass cannot rule out the supersoft high-density $E_{\mathrm{sym}}(n)$. Furthermore, we find the stiffer high-density $E_{\mathrm{sym}}(n)$ based on the existence of $2.14M_{\odot }$ NSs leads to a strong constraint of ${\Lambda }_{1.4}\ge 348_{-51}^{+88}$ for the dimensionless tidal deformability of the canonical $1.4M_{\odot }$ NS.

   ↳ nucl-thastro-ph.HEastro-ph.SRhep-ph+1ApJ(2019)·33 citations
8. 08*

   Can We Observe Jet $P_T$-broadening in Heavy-Ion Collisions at the LHC?

   Felix Ringer🇺🇸 · Bo-Wen Xiao🇨🇳 · Feng Yuan🇺🇸

   We investigate the effect of PT-broadening on jet substructure observables in heavy-ion collisions at the LHC. As an example, we focus on the opening angle of the two branches that satisfy the soft drop grooming condition in a highly energetic jet. The medium modification of the angular distribution can provide important information on the jet transport properties of hot QCD matter. In addition, we take into account a change of the overall fraction of quark and gluon jets in heavy-ion collisions. We comment on the comparison to a recent measurement from the ALICE Collaboration.

   ↳ hep-phnucl-exnucl-thPLB(2020)·58 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.