Mon·Nov 15, 2021Monday·November 15, 2021

1. 01*

   Measurements of azimuthal anisotropies of jet production in Pb+Pb collisions at $\sqrt{s_{NN}}=$ 5.02 TeV with the ATLAS detector

   ATLAS Collaboration

   The azimuthal variation of jet yields in heavy-ion collisions provides information about the path-length dependence of the energy loss experienced by partons passing through the hot, dense nuclear matter known as the quark-gluon plasma. This paper presents the azimuthal anisotropy coefficients $v_2$, $v_3$, and $v_4$ measured for jets in Pb+Pb collisions at $\sqrt{s_{NN}}=$ 5.02 TeV using the ATLAS detector at the LHC. The measurement uses data collected in 2015 and 2018, corresponding to an integrated luminosity of 2.2 nb${}^{-1}$. The $v_n$ values are measured as a function of the transverse momentum of the jets between 71 GeV and 398 GeV and the event centrality. A nonzero value of $v_2$ is observed in all but the most central collisions. The value of $v_2$ is largest for jets with lower transverse momentum, with values up to 0.05 in mid-central collisions. A smaller, nonzero value of $v_3$ of approximately 0.01 is measured with no significant dependence on jet $p_T$ or centrality, suggesting that fluctuations in the initial state play a small but distinct role in jet energy loss. No significant deviation of $v_4$ from zero is observed in the measured kinematic region.

   nucl-exhep-exPRC(2022)·66 citations
2. 02*

   K${}_{\mathrm{S}}^0$K${}_{\mathrm{S}}^0$ and K${}_{\mathrm{S}}^0$K${}^{\pm }$ femtoscopy in pp collisions at $\sqrt{s}=$ 5.02 and 13 TeV

   ALICE Collaboration

   Femtoscopic correlations with the particle pair combinations K${}_{\mathrm{S}}^0$K${}_{\mathrm{S}}^0$ and K${}_{\mathrm{S}}^0$K${}^{\pm }$ are studied in pp collisions at $\sqrt{s}=5.02$ and $13$ TeV by the ALICE experiment. At both energies, boson source parameters are extracted for both pair combinations, by fitting models based on Gaussian size distributions of the sources, to the measured two-particle correlation functions. The interaction model used for the K${}_{\mathrm{S}}^0$K${}_{\mathrm{S}}^0$ analysis includes quantum statistics and strong final-state interactions through the $f_0(980)$ and $a_0(980)$ resonances. The model used for the K${}_{\mathrm{S}}^0$K${}^{\pm }$ analysis includes only the final-state interaction through the $a_0$ resonance. Source parameters extracted in the present work are compared with published values from pp collisions at $\sqrt{s}=$ 7 TeV and the different pair combinations are found to be consistent. From the observation that the strength of the K${}_{\mathrm{S}}^0$K${}_{\mathrm{S}}^0$ correlations is significantly greater than the strength of the K${}_{\mathrm{S}}^0$K${}^{\pm }$ correlations, the new results are compatible with the $a_0$ resonance being a tetraquark state of the form $(q_1,\overline{q_2},s,\overline{s})$, where $q_1$ and $q_2$ are $u$ or $d$ quarks.

   nucl-exhep-exPLB(2022)·33 citations
3. 03*

   Semileptonic transitions: $B_{(s)}\to \pi (K)$; $D_s\to K$; $D\to \pi ,K$; and $K\to \pi$

   Zhao-Qian Yao🇨🇳 · Daniele Binosi🇮🇹 · Zhu-Fang Cui🇨🇳 · Craig D. Roberts🇨🇳

   Continuum Schwinger function methods for the strong-interaction bound-state problem are used to arrive at a unified set of parameter-free predictions for the semileptonic $K\to \pi$, $D\to \pi ,K$ and $D_s\to K$, $B_{(s)}\to \pi (K)$ transition form factors and the associated branching fractions. The form factors are a leading source of uncertainty in all such calculations: our results agree quantitatively with available data and provide benchmarks for the hitherto unmeasured $D_s\to K^0$, ${\bar{B}}_s\to K^{+}$ form factors. The analysis delivers a value of $|V_{cs}|=0.974(10)$ and also predictions for all branching fraction ratios in the pseudoscalar meson sector that can be used to test lepton flavour universality. Quantitative comparisons are provided between extant theory and the recent measurement of ${\mathcal{B}}_{B_s^0\to K^{-}{\mu }^{+}{\nu }_{\mu }}$. Here, further, refined measurements would be useful in moving toward a more accurate value of $|V_{ub}|$.

   ↳ hep-phhep-exhep-latnucl-ex+1PLB(2022)·19 citations
4. 04*

   Ricochet Progress and Status

   Ricochet Collaboration: G. Beaulieu · V. Belov · L. Berge · J. Billard · G. Bres · J-.L. Bret · A. Broniatowski · M. Calvo · A. Cazes · D. Chaize · M. Chapellier · L. Chaplinsky and 67 other authors

   We present an overview of recent progress towards the Ricochet coherent elastic neutrino nucleus scattering CE$\nu$NS experiment. The ILL research reactor in Grenoble, France has been selected as the experiment site, after in situ studies of vibration and particle backgrounds. We present background rate estimates specific to that site, along with descriptions of the planned CryoCube and Q-Array detector payloads.

   ↳ physics.ins-detnucl-exJ.Low Temp.Phys.(2023)·51 citations
5. 05*

   Background Estimation Studies for Positron Double Beta Decay

   Swati Thakur🇮🇳 · A. Mazumdar · R. Shah · V. Vatsa🇮🇳 · V. Nanal🇮🇳 · M.S. Pose🇮🇳 · Pushpendra P. Singh🇮🇳 · P.K. Raina🇮🇳 · R.G. Pillay🇮🇳

   The study of neutrinoless double beta decay has attracted much attention as it can provide valuable information about the mass and the nature of the neutrino. The double beta decay (DBD) itself is also of interest in nuclear physics. While DBD has been observed in about a dozen nuclei, the positron double beta decay (${\beta }^{+}{\beta }^{+}$/EC-${\beta }^{+}$) continues to be an elusive. An important signature for ${\beta }^{+}{\beta }^{+}$ decay is the simultaneous emission of four 511 keV gamma rays and the coincident detection of these gamma rays can improve the measurement sensitivity. This paper presents an estimation of sensitivity for EC-${\beta }^{+}$ and ${\beta }^{+}{\beta }^{+}$ employing coincidence measurement with two high purity Ge (HPGe) detectors. Simulations for coincident detection efficiency (${ϵ}_c$) of 511 keV gamma rays with two HPGe detectors have been carried out using GEANT4 for different source geometries to optimize the mass efficiency product (M${ϵ}_c$). The source of size $55mm\times 55mm\times 5mm$ (thickness) sandwiched between the front faces of the detectors were found to be optimal for 2 pairs of 511 keV gamma rays in the present detector setup. The coincident background is estimated at the sea level with moderate Pb shielding. With this setup, the sensitivity for T${}_{1/2}$ measurement of EC-${\beta }^{+}$ in ${}^{112}$Sn and ${\beta }^{+}{\beta }^{+}$ in ${}^{106}$Cd is estimated to be $\sim$10${}^{19}$ - 10${}^{20}$ y for 1y of measurement time.

   ↳ physics.ins-detnucl-ex1 citation

* 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.