JINST

The Baikal-GVD is a neutrino telescope situated in the deepest freshwater lake in the world — Lake Baikal. The design of the Baikal-GVD trigger system allows also to study the ambient light of the lake. The analysis of the optical light activity of Baikal water, particularly, time and spatial variations of the luminescence activity for data collected in years 2018, 2019, and 2020 is presented. For the first time we observed highly luminescent layer moving upwards with maximal speed of 28 m/day in January 2021.

Eur. Phys. J. C

The search for neutrino events in correlation with 42 most intense fast radio bursts (FRBs) has been performed using the Borexino dataset from 05/2007 to 06/2021. We have searched for signals with visible energies above 250 keV within a time window of $\pm \, 1000$ s corresponding to detection time of a particular FRB. We also applied an alternative approach based on searching for specific shapes of neutrino-electron scattering spectra in the full exposure data of the Borexino detector. In particular, two incoming neutrino spectra were considered: the monoenergetic line and the spectrum expected from supernovae. The same spectra were considered for electron antineutrinos detected through inverse beta-decay reaction. No statistically significant excess over the background was observed. As a result, the strongest upper limits on FRB-associated neutrino fluences of all flavors have been obtained in the 0.5–50 MeV neutrino energy range.

Phys. Rev. Lett.

The differential cross sections of the ${\mathrm{\Sigma }}^{-}p\to \mathrm{\Lambda }n$ reaction were measured accurately for the ${\mathrm{\Sigma }}^{-}$ momentum ($p_{\mathrm{\Sigma }}$) ranging from 470 to $650\mathrm{MeV}/c$ at the J-PARC Hadron Experimental Facility. Precise angular information about the ${\mathrm{\Sigma }}^{-}p\to \mathrm{\Lambda }n$ reaction was obtained for the first time by detecting approximately 100 reaction events at each angular step of $\mathrm{\Delta }\cos \theta =0.1$. The obtained differential cross sections show a slightly forward-peaking structure in the measured momentum regions. The cross sections integrated for $-0.7\le \cos \theta \le 1.0$ were obtained as $22.5\pm 0.68$ [statistical error(stat.)] $\pm 0.65$ [systematic error(syst.)] mb and $15.8\pm 0.83(\mathrm{stat})\pm 0.52(\mathrm{syst})\mathrm{mb}$ for $470<p_{\mathrm{\Sigma }}(\mathrm{MeV}/c)<550$ and $550<p_{\mathrm{\Sigma }}(\mathrm{MeV}/c)<650$, respectively. These results show a drastic improvement compared with past measurements of the hyperon-proton scattering experiments. They will play essential roles in updating the theoretical models of the baryon-baryon interactions.

Phys.Rev.D

Using a data sample of $4.481\times 10^8 \psi^\prime$ events collected with the BESIII detector, we report the first observation of the four-lepton-decays $J/\psi\to e^+e^-e^+e^-$ and $J/\psi\to e^+e^-\mu^+\mu^-$ utilizing the process $\psi^\prime\to \pi^+\pi^- J/\psi$. The branching fractions are determined to be $[5.48\pm0.31~(\rm stat)\pm0.45~(\rm syst)]\times 10^{-5}$ and $[3.53~\pm0.22~(\rm stat)\pm0.13~(\rm syst)]\times 10^{-5}$, respectively. The results are consistent with theoretical predictions. No significant signal is observed for $J/\psi\to \mu^+\mu^-\mu^+\mu^-$, and an upper limit on the branching fraction is set at $1.6\times 10^{-6}$ at the 90$\%$ confidence level. A CP asymmetry observable is constructed for the first two channels, which is measured to be $(-0.012\pm0.054\pm0.010)$ and $(0.062\pm0.059\pm0.006)$, respectively. No evidence for CP violation is observed in this process.

JHEP

A search for the decay h$_{c}$→ π$^{0}$J/ψ is performed using a sample of hc produced in the reaction e$^{+}$e$^{−}$→ π$^{+}$π$^{−}$h$_{c}$. The data samples were collected with the BESIII detector at center-of-mass energies between 4.189 and 4.437 GeV, corresponding to a total integrated luminosity of 11 fb$^{−1}$. No significant signal is observed. Upper limits on the branching ratio $ \mathcal{B} $(h$_{c}$→ π$^{0}$J/ψ)/$ \mathcal{B} $(h$_{c}$→ γη$_{c}$→ γK$^{+}$K$^{−}$π$^{0}$) and on the branching fraction $ \mathcal{B} $(h$_{c}$→ π$^{0}$J/ψ) are determined to be 7.5 × 10$^{−2}$ and 4.7 × 10$^{−4}$ at 90% confidence level, respectively. The latter is derived from the former using the measured branching fraction of the normalization channel. This is the first determination of the upper limit of the decay h$_{c}$→ π$^{0}$J/ψ.[graphic not available: see fulltext]

Phys. Rev. D

Differential cross section measurements of $W^{\pm }\gamma$ production in proton-proton collisions at $\sqrt{s}=13\mathrm{TeV}$ are presented. The data set used in this study was collected with the CMS detector at the CERN LHC in 2016–2018 with an integrated luminosity of $138{\mathrm{fb}}^{-1}$. Candidate events containing an electron or muon, a photon, and missing transverse momentum are selected. The measurements are compared with standard model predictions computed at next-to-leading and next-to-next-to-leading orders in perturbative quantum chromodynamics. Constraints on the presence of TeV-scale new physics affecting the $WW\gamma$ vertex are determined within an effective field theory framework, focusing on the ${\mathcal{O}}_{3W}$ operator. A simultaneous measurement of the photon transverse momentum and the azimuthal angle of the charged lepton in a special reference frame is performed. This two-dimensional approach provides up to a factor of ten more sensitivity to the interference between the standard model and the ${\mathcal{O}}_{3W}$ contribution than using the transverse momentum alone.

J. Open Source Softw.

Current neutrino detectors will observe hundreds to thousands of neutrinos from a Galactic supernova, and future detectors will increase this yield by an order of magnitude or more. With such neutrino data sets, the next Galactic supernova will significantly increase our un- derstanding of the explosions of massive stars, nuclear physics under extreme conditions, and the fundamental properties of neutrinos. However, there is a gulf between supernova simu- lations and the corresponding signals in detectors, making comparisons between theory and observation, as well as between different detectors, very difficult. SNEWPY offers a unified interface for hundreds of supernova simulations, a large library of flux transformations on the way towards the detector, and an interface to SNOwGLoBES (Scholberg & SNOwGLoBES Contributors, 2021), allowing users to easily calculate and compare expected event rates from many supernova models in many different neutrino detectors.

JHEP

A search has been performed for heavy resonances decaying to ZZ or ZW and for axion-like particles (ALPs) mediating nonresonant ZZ or ZH production, in final states with two charged leptons (ℓ = e, μ) produced by the decay of a Z boson, and two quarks produced by the decay of a Z, W, or Higgs boson H. The analysis is sensitive to resonances with masses in the range 450 to 2000 GeV. Two categories are defined corresponding to the merged or resolved reconstruction of the hadronically decaying boson. The search is based on data collected during 2016–2018 by the CMS experiment at the LHC in proton-proton collisions at a center-of-mass energy of 13 TeV, corresponding to an integrated luminosity of 138 fb$^{−1}$. No significant excess is observed in the data above the standard model background expectation. Upper limits on the production cross section of heavy, narrow spin-2 and spin-1 resonances are derived as functions of the resonance mass, and exclusion limits on the production of bulk graviton particles and W′ bosons are calculated in the framework of the warped extra dimensions and heavy vector triplet models, respectively. In addition, upper limits on the ALP-mediated diboson production cross section and ALP couplings to standard model particles are obtained in the framework of linear and chiral effective field theories. These are the first limits on nonresonant ALP-mediated ZZ and ZH production obtained by the LHC experiments.[graphic not available: see fulltext]

Phys. Rev. D

Using a data sample of $\psi (3770)$ events collected with the BESIII detector at BEPCII corresponding to an integrated luminosity of $2.9{\mathrm{fb}}^{-1}$, we report a measurement of $\mathrm{\Lambda }$ spin polarization in $e^{+}{e}^{-}\to \mathrm{\Lambda }\overline{\mathrm{\Lambda }}$ at $\sqrt{s}=3.773\mathrm{GeV}$. The significance of polarization is found to be $2\sigma$ including the systematic uncertainty, which implies a zero phase between the transition amplitudes of the $\mathrm{\Lambda }\overline{\mathrm{\Lambda }}$ helicity states. This phase can be interpreted in terms of psionic form factors, and is determined to be $\mathrm{\Delta }{\mathrm{\Phi }}^{\mathrm{\Psi }}={\mathrm{\Phi }}_E^{\mathrm{\Psi }}-{\mathrm{\Phi }}_M^{\mathrm{\Psi }}=(71_{-46}^{+66}\pm 5)°$. Similarly, the ratio between the form factors is found to be $R^{\psi }=|G_E^{\mathrm{\Psi }}/G_M^{\mathrm{\Psi }}|=0.48_{-0.35}^{+0.21}\pm 0.03$. The first uncertainties are statistical and the second systematic.

JHEP

Searches for rare $ {B}_s^0 $ and B$^{0}$ decays into four muons are performed using proton-proton collision data recorded by the LHCb experiment, corresponding to an integrated luminosity of 9 fb$^{−1}$. Direct decays and decays via light scalar and J/ψ resonances are considered. No evidence for the six decays searched for is found and upper limits at the 95% confidence level on their branching fractions ranging between 1.8 × 10$^{−10}$ and 2.6 × 10$^{−9}$ are set.[graphic not available: see fulltext]

Phys.Rev.D

The photon polarization in $b\to s\gamma$ transitions is measured for the first time in radiative $b$ -baryon decays exploiting the unique spin structure of ${\mathrm{\Lambda }}_b^0\to \mathrm{\Lambda }\gamma$ decays. A data sample corresponding to an integrated luminosity of $6{\mathrm{fb}}^{-1}$ collected by the LHCb experiment in $pp$ collisions at a center-of-mass energy of 13 TeV is used. The photon polarization is measured to be ${\alpha }_{\gamma }=0.82_{-0.26-0.13}^{+0.17+0.04}$, where the first uncertainty is statistical and the second systematic. This result is in agreement with the Standard Model prediction and previous measurements in $b$ -meson decays. Charge-parity breaking effects are studied for the first time in this observable and found to be consistent with $CP$ symmetry.

JHEP

A search for a heavy resonance decaying into a top quark and a W boson in proton-proton collisions at $ \sqrt{s} $ = 13 TeV is presented. The data analyzed were recorded with the CMS detector at the LHC and correspond to an integrated luminosity of 138 fb$^{−1}$. The top quark is reconstructed as a single jet and the W boson, from its decay into an electron or muon and the corresponding neutrino. A top quark tagging technique based on jet clustering with a variable distance parameter and simultaneous jet grooming is used to identify jets from the collimated top quark decay. The results are interpreted in the context of two benchmark models, where the heavy resonance is either an excited bottom quark b$^{∗}$ or a vector-like quark B. A statistical combination with an earlier search by the CMS Collaboration in the all-hadronic final state is performed to place upper cross section limits on these two models. The new analysis extends the lower range of resonance mass probed from 1.4 down to 0.7 TeV. For left-handed, right-handed, and vector-like couplings, b$^{∗}$ masses up to 3.0, 3.0, and 3.2 TeV are excluded at 95% confidence level, respectively. The observed upper limits represent the most stringent constraints on the b$^{∗}$ model to date.[graphic not available: see fulltext]

JHEP

A measurement of the inclusive jet production in proton-proton collisions at the LHC at $ \sqrt{s} $ = 13 TeV is presented. The double-differential cross sections are measured as a function of the jet transverse momentum p$_{T}$ and the absolute jet rapidity |y|. The anti-k$_{T}$ clustering algorithm is used with distance parameter of 0.4 (0.7) in a phase space region with jet p$_{T}$ from 97 GeV up to 3.1 TeV and |y| < 2.0. Data collected with the CMS detector are used, corresponding to an integrated luminosity of 36.3 fb$^{−1}$ (33.5 fb$^{−1}$). The measurement is used in a comprehensive QCD analysis at next-to-next-to-leading order, which results in significant improvement in the accuracy of the parton distributions in the proton. Simultaneously, the value of the strong coupling constant at the Z boson mass is extracted as α$_{S}$(m$_{Z}$) = 0.1170±0.0019. For the first time, these data are used in a standard model effective field theory analysis at next-to-leading order, where parton distributions and the QCD parameters are extracted simultaneously with imposed constraints on the Wilson coefficient c$_{1}$ of 4-quark contact interactions.[graphic not available: see fulltext]

JINST

The fast luminescence component of barium fluoride (BaF_2) crystals with a subnanosecond decay time can find wide application in particle physics and nuclear physics. However, the slow luminescence component with the 630 ns decay time could cause pile-up signals at a high rate environment. Doping of BaF$_{2}$ crystals with rare earth elements suppresses the slow emission component, but at the same time the radiation hardness of the crystals deteriorates. This work presents the results of studying crystal samples, both pure BaF$_{2}$ and those doped with yttrium in a proportion of 1 at.%Y, 3 at.%Y and 5 at.%Y, irradiated with a fast neutron fluence of about 2.3×10$^{14}$ n/cm$^{2}$. Their light output and decay kinetics were measured before and after irradiation. It is found that the light output loss of a pure BaF$_{2}$ crystal after irradiation is about 7%, and the light output loss of yttrium doped samples after irradiation is about two times higher. The measurement results demonstrate that after irradiation the fast component of each sample has a relative light output loss 2–3% larger than the slow one.

JINST

The Majorana Demonstrator comprises two arrays of high-purity germanium detectors constructed to search for neutrinoless double-beta decay in $^{76}$Ge and other physics beyond the Standard Model. Its readout electronics were designed to have low electronic noise, and radioactive backgrounds were minimized by using low-mass components and low-radioactivity materials near the detectors. This paper provides a description of all components of the Majorana Demonstrator readout electronics, spanning the front-end electronics and internal cabling, back-end electronics, digitizer, and power supplies, along with the grounding scheme. The spectroscopic performance achieved with these readout electronics is also demonstrated.

Phys.Lett.B

A search for invisible decays of the Higgs boson as well as searches for dark matter candidates, produced together with a leptonically decaying Z boson, are presented. The analysis is performed using proton−proton collisions at a centre-of-mass energy of 13 TeV, delivered by the LHC, corresponding to an integrated luminosity of 139${\text{fb}}^{-1}$ and recorded by the ATLAS experiment. Assuming Standard Model cross-sections for ZH production, the observed (expected) upper limit on the branching ratio of the Higgs boson to invisible particles is found to be 19% (19%) at the 95% confidence level. Exclusion limits are also set for simplified dark matter models and two-Higgs-doublet models with an additional pseudoscalar mediator.

Phys. Rev. D

This paper reports constraints on Higgs boson production with transverse momentum above 1 TeV. The analyzed data from proton–proton collisions at a center-of-mass energy of 13 TeV were recorded with the ATLAS detector at the Large Hadron Collider from 2015 to 2018 and correspond to an integrated luminosity of $136{\mathrm{fb}}^{-1}$. Higgs bosons decaying into $b\overline{b}$ are reconstructed as single large-radius jets recoiling against a hadronic system and are identified by the experimental signature of two $b$-hadron decays. The experimental techniques are validated in the same kinematic regime using the $Z\to b\overline{b}$ process. The 95% confidence-level upper limit on the cross section for Higgs boson production with transverse momentum above 450 GeV is 115 fb, and above 1 TeV it is 9.6 fb. The Standard Model cross section predictions for a Higgs boson with a mass of 125 GeV in the same kinematic regions are 18.4 fb and 0.13 fb, respectively.

Nucl. Instrum. Meth. A

The strategies for and the performance of the CMS silicon tracking system alignment during the 2015-2018 data-taking period of the LHC are described. The alignment procedures during and after data taking are explained. Alignment scenarios are also derived for use in the simulation of the detector response. Systematic effects, related to intrinsic symmetries of the alignment task or to external constraints, are discussed and illustrated for different scenarios.

Chin.Phys.C

Using inclusive decays of , a precise determination of the number of events collected with the BESIII detector was performed. For the two data sets taken in 2009 and 2012, the numbers of events were recalculated to be and , respectively; these numbers are in good agreement with the previous measurements. For the sample taken in 2017–2019, the number of events was determined to be . The total number of events collected with the BESIII detector was determined to be , where the uncertainty is dominated by systematic effects, and the statistical uncertainty is negligible.

Phys.Rev.C

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 $\text{Pb}+\text{Pb}$ collisions at $\sqrt{s_{\mathrm{NN}}}=5.02$ 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 ${\mathrm{nb}}^{-1}$. The $v_n$ values are measured as a function of the transverse momentum of the jets between 71 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 $p_{\mathrm{T}}$ 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.

JHEP

The associated production of a Higgs boson and a top-quark pair is measured in events characterised by the presence of one or two electrons or muons. The Higgs boson decay into a $b$-quark pair is used. The analysed data, corresponding to an integrated luminosity of 139 fb$^{-1}$, were collected in proton-proton collisions at the Large Hadron Collider between 2015 and 2018 at a centre-of-mass energy of $\sqrt{s}=13$ TeV. The measured signal strength, defined as the ratio of the measured signal yield to that predicted by the Standard Model, is $0.35^{+0.36}_{-0.34}$. This result is compatible with the Standard Model prediction and corresponds to an observed (expected) significance of 1.0 (2.7) standard deviations. The signal strength is also measured differentially in bins of the Higgs boson transverse momentum in the simplified template cross-section framework, including a bin for specially selected boosted Higgs bosons with transverse momentum above 300 GeV.

Phys. Rev. D

Based on $3.19{\mathrm{fb}}^{-1}$ of $e^{+}{e}^{-}$ collision data accumulated at the center-of-mass energy 4.178 GeV with the BESIII detector operating at the BEPCII collider, the electromagnetic Dalitz decay $D^{*0}\to D^0{e}^{+}{e}^{-}$ is observed for the first time with a statistical significance of $13.2\sigma$. The ratio of the branching fraction of $D^{*0}\to D^0{e}^{+}{e}^{-}$ to that of $D^{*0}\to D^0\gamma$ is measured to be $(11.08\pm 0.76\pm 0.49)\times {10}^{-3}$. By using the world average value of the branching fraction of $D^{*0}\to D^0\gamma$, the branching fraction of $D^{*0}\to D^0{e}^{+}{e}^{-}$ is determined to be $(3.91\pm 0.27\pm 0.17\pm 0.10)\times {10}^{-3}$, where the first uncertainty is statistical, the second is systematic and the third is from external input of the branching fraction for $D^{*0}\to D^0\gamma$.

J.Low Temp.Phys.

We present an overview of recent progress toward 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.

JINST

The Compact Muon Solenoid collaboration is designing a new high-granularity endcap calorimeter, HGCAL, to be installed later this decade. As part of this development work, a prototype system was built, with an electromagnetic section consisting of 14 double-sided structures, providing 28 sampling layers. Each sampling layer has an hexagonal module, where a multipad large-area silicon sensor is glued between an electronics circuit board and a metal baseplate. The sensor pads of approximately 1.1 cm$^{2}$ are wire-bonded to the circuit board and are readout by custom integrated circuits. The prototype was extensively tested with beams at CERN's Super Proton Synchrotron in 2018. Based on the data collected with beams of positrons, with energies ranging from 20 to 300 GeV, measurements of the energy resolution and linearity, the position and angular resolutions, and the shower shapes are presented and compared to a detailed Geant4 simulation.

JHEP

A search for supersymmetry in events with two or three low-momentum leptons and missing transverse momentum is performed. The search uses proton-proton collisions at $ \sqrt{s} $ = 13 TeV collected in the three-year period 2016–2018 by the CMS experiment at the LHC and corresponding to an integrated luminosity of up to 137 fb$^{−1}$. The data are found to be in agreement with expectations from standard model processes. The results are interpreted in terms of electroweakino and top squark pair production with a small mass difference between the produced supersymmetric particles and the lightest neutralino. For the electroweakino interpretation, two simplified models are used, a wino-bino model and a higgsino model. Exclusion limits at 95% confidence level are set on $ {\overset{\sim }{\upchi}}_2^0/{\overset{\sim }{\upchi}}_1^{\pm } $ masses up to 275 GeV for a mass difference of 10 GeV in the wino-bino case, and up to 205(150) GeV for a mass difference of 7.5 (3) GeV in the higgsino case. The results for the higgsino are further interpreted using a phenomenological minimal supersymmetric standard model, excluding the higgsino mass parameter μ up to 180 GeV with the bino mass parameter M$_{1}$ at 800 GeV. In the top squark interpretation, exclusion limits are set at top squark masses up to 540 GeV for four-body top squark decays and up to 480 GeV for chargino-mediated decays with a mass difference of 30 GeV.[graphic not available: see fulltext]