Phys.Rev.Lett.

Using $e^{+}{e}^{-}$ collision data corresponding to an integrated luminosity of $19{\mathrm{fb}}^{-1}$ collected by the BESIII detector at center-of-mass energies ranging from 4.13 to 4.70 GeV, we report the first evidence for a new excited ${\mathrm{\Omega }}^{-}$ hyperon, the $\mathrm{\Omega }(2109{)}^{-}$, through the process $e^{+}{e}^{-}\to \mathrm{\Omega }(2109{)}^{-}{\overline{\mathrm{\Omega }}}^{+}+\mathrm{c}.\mathrm{c}.$ with a significance of $4.1\sigma$. The mass and width of $\mathrm{\Omega }(2109{)}^{-}$ are measured to be $2108.5\pm {5.2}_{\mathrm{stat}}\pm {0.9}_{\mathrm{syst}}\mathrm{MeV}/c^2$ and $18.3\pm {16.4}_{\mathrm{stat}}\pm {5.7}_{\mathrm{syst}}\mathrm{MeV}$, respectively. We also present evidence for a new production mechanism for the previously identified $\mathrm{\Omega }(2012{)}^{-}$ via the process $e^{+}{e}^{-}\to \mathrm{\Omega }(2012{)}^{-}{\overline{\mathrm{\Omega }}}^{+}+\mathrm{c}.\mathrm{c}.$ with a significance of $3.5\sigma$.

Phys. Rev. Lett.

A search is presented for fractionally charged particles with charges below $1e$, using their small energy loss in the tracking detector as a key variable to observe a signal. The analyzed dataset corresponds to an integrated luminosity of $138{\mathrm{fb}}^{-1}$ of proton-proton collisions collected at $\sqrt{s}=13\mathrm{TeV}$ in 2016–2018 at the CERN LHC. This is the first search at the LHC for new particles with a charge between $e/3$ and $0.9e$, including an extension of previous results at a charge of $2e/3$. Masses up to 640 GeV and charges as low as $e/3$ are excluded at 95% confidence level. These are the most stringent limits to date for the considered Drell-Yan-like production mode.

Phys.Rev.Lett.

Lepton flavor universality in rare $b\to s$ transitions is tested for the first time using $B_s^0$ meson decays. The measurements are performed using $pp$ collision data collected by the LHCb experiment between 2011 and 2018, corresponding to a total integrated luminosity of $9{\mathrm{fb}}^{-1}$. Branching fraction ratios between the $B_s^0\to \varphi e^{+}{e}^{-}$ and $B_s^0\to \varphi {\mu }^{+}{\mu }^{-}$ decays are measured in three regions of dilepton mass squared, $q^2$, with $0.1<q^2<1.1$, $1.1<q^2<6.0$, and $15<q^2<19{\mathrm{GeV}}^2/c^4$. The results agree with the standard model expectation of lepton flavor universality.

Phys. Rev. Lett.

A search is performed for dark matter particles produced in association with a resonantly produced pair of $b$-quarks with $30<m_{bb}<150\mathrm{GeV}$ using $140{\mathrm{fb}}^{-1}$ of proton-proton collisions at a center-of-mass energy of 13 TeV recorded by the ATLAS detector at the LHC. This signature is expected in extensions of the standard model predicting the production of dark matter particles, in particular those containing a dark Higgs boson $s$ that decays into $b\overline{b}$. The highly boosted $s\to b\overline{b}$ topology is reconstructed using jet reclustering and a new identification algorithm. This search places stringent constraints across regions of the dark Higgs model parameter space that satisfy the observed relic density, excluding dark Higgs bosons with masses between 30 and 150 GeV in benchmark scenarios with $Z^{\prime }$ mediator masses up to 4.8 TeV at 95% confidence level.

JHEP

We report an improved study of the semileptonic decay ${D}^0\to {\overline{K}}^0{\pi}^{-}{e}^{+}{\nu}_e$ based on a sample of 7.9 fb$^{−1}$ of e$^{+}$e$^{−}$ annihilation data collected at a center-of-mass energy of 3.773 GeV with the BESIII detector at the BEPCII collider. The branching fraction of this decay is measured to be $\mathcal{B}\left({D}^0\to {\overline{K}}^0{\pi}^{-}{e}^{+}{\nu}_e\right)$ = (1.444 ± 0.022$_{stat}$ ± 0.024$_{syst}$)%, which is the most precise to date, where the first uncertainty is statistical and the second is systematic. Based on investigation of the decay dynamics, we find that the decay is dominated by the K$^{*}$(892)$^{−}$ component and present an improved measurement of its branching fraction to be $\mathcal{B}\left({D}^0\to {K}^{\ast }{(892)}^{-}{e}^{+}{\nu}_e\right)$ = (2.039 ± 0.032$_{stat}$± 0.034$_{syst}$)%. We also determine the ratios of the hadronic form factors for the K$^{*}$(892)$^{−}$e$^{+}$ν$_{e}$ decay to be r$_{V}$ = V(0)/A$_{1}$(0) = 1.48 ± 0.05$_{stat}$± 0.02$_{syst}$ and r$_{2}$ = A$_{2}$(0)/A$_{1}$(0) = 0.70 ± 0.04$_{stat}$± 0.02$_{syst}$, where V(0) is the vector form factor and A$_{1,2}$(0) are the axial form factors. In addition, the ${\overline{K}}^0{\pi}^{-} \mathcal{S}$-wave component is found to account for (5.87 ± 0.32$_{stat}$± 0.16$_{syst}$)% of the total decay rate, corresponding to a branching fraction of $B\left[{D}^0\to {\left({\overline{K}}^0{\pi}^{-}\right)}_{S-\textrm{wave}}{e}^{+}{\nu}_e\right]$ = (0.085 ± 0.005$_{stat}$± 0.003$_{syst}$)%.[graphic not available: see fulltext]

JHEP

A search for exotic decays of the 125 GeV Higgs boson into a pair of new spin-0 particles, H → aa, where one decays into a photon pair and the other into a τ-lepton pair, is presented. Hadronic decays of the τ-leptons are considered and reconstructed using a dedicated tagger for collimated τ-lepton pairs. The search uses 140 fb$^{−1}$ of proton-proton collision data at a centre-of-mass energy of $\sqrt{s}$ = 13 TeV recorded between 2015 and 2018 by the ATLAS experiment at the Large Hadron Collider. The search is performed in the mass range of the a boson between 10 GeV and 60 GeV. No significant excess of events is observed above the Standard Model background expectation. Model-independent upper limits at 95% confidence level are set on the branching ratio of the Higgs boson to the γγττ final state, $\mathcal{B}$(H → aa → γγττ), ranging from 0.2% to 2%, depending on the a-boson mass hypothesis.[graphic not available: see fulltext]

Eur.Phys.J.C

A search is presented for the pair production of new heavy resonances, each decaying into a top quark (t) or antiquark and a gluon (g). The analysis uses data recorded with the CMS detector from proton-proton collisions at a center-of-mass energy of 13 TeV at the LHC, corresponding to an integrated luminosity of 138 fb$^{-1}$. Events with one muon or electron, multiple jets, and missing transverse momentum are selected. After using a deep neural network to enrich the data sample with signal-like events, distributions in the scalar sum of the transverse momenta of all reconstructed objects are analyzed in the search for a signal. No significant deviations from the standard model prediction are found. Upper limits at 95% confidence level are set on the product of cross section and branching fraction squared for the pair production of excited top quarks in the $\mathrm{t^*}$ $\to$ tg decay channel. The upper limits range from 120 to 0.8 fb for a $\mathrm{t^*}$ with spin-1/2 and from 15 to 1.0 fb for a $\mathrm{t^*}$ with spin-3/2. These correspond to mass exclusion limits up to 1050 and 1700 GeV for spin-1/2 and spin-3/2 $\mathrm{t^*}$ particles, respectively. These are the most stringent limits to date on the existence of $\mathrm{t^*}$ $\to$ tg resonances.

Eur. Phys. J. C

A search for a dark photon, a new light neutral particle, which decays promptly into collimated pairs of electrons or muons is presented. The search targets dark photons resulting from the exotic decay of the Standard Model Higgs boson, assuming its production via the dominant gluon-gluon fusion mode. The analysis is based on $140~\hbox {fb}^{-1}$ of data collected with the ATLAS detector at the Large Hadron Collider from proton-proton collisions at a center-of-mass energy of 13 $\text {T}\text {e}\hspace{-1.00006pt}\text {V}$. Events with collimated pairs of electrons or muons are analysed and background contributions are estimated using data-driven techniques. No significant excess in the data above the Standard Model background is observed. Upper limits are set at 95% confidence level on the branching ratio of the Higgs boson decay into dark photons between 0.001% and 5%, depending on the assumed dark photon mass and signal model.

Nature Commun.

Strong interactions preserve an approximate isospin symmetry between up (u) and down (d) quarks, part of the more general flavor symmetry. In the case of K meson production, if this isospin symmetry were exact, it would result in equal numbers of charged (K$^{+}$ and K$^{−}$) and neutral (K$^{0}$ and ${\overline{K}}^{0}$) mesons produced in collisions of isospin-symmetric atomic nuclei. Here, we report results on the relative abundance of charged over neutral K meson production in argon and scandium nuclei collisions at a center-of-mass energy of 11.9 GeV per nucleon pair. We find that the production of K$^{+}$ and K$^{−}$ mesons at mid-rapidity is (18.4 ± 6.1)% higher than that of the neutral K mesons. Although with large uncertainties, earlier data on nucleus-nucleus collisions in the collision center-of-mass energy range $2.6 \, < \, \sqrt{{s}_{NN}} \, < \, 200$ GeV are consistent with the present result. Using well-established models for hadron production, we demonstrate that known isospin-symmetry breaking effects and the initial nuclei containing more neutrons than protons lead only to a small (few percent) deviation of the charged-to-neutral kaon ratio from unity at high energies. Thus, they cannot explain the measurements. The significance of the flavor-symmetry violation beyond the known effects is 4.7σ when the compilation of world data with uncertainties quoted by the experiments is used. New systematic, high-precision measurements and theoretical efforts are needed to establish the origin of the observed large isospin-symmetry breaking.

Phys. Lett. B

A full set of optimized observables is measured in an angular analysis of the decay ${\mathrm{B}}^0\to {\mathrm{K}}^{⁎}{(892)}^0{\mathrm{\mu }}^{+}{\mathrm{\mu }}^{-}$ using a sample of proton-proton collisions at $\sqrt{s}=13\text{TeV}$, collected with the CMS detector at the LHC, corresponding to an integrated luminosity of 140${\text{fb}}^{-1}$. The analysis is performed in six bins of the squared invariant mass of the dimuon system, $q^2$, over the range $1.1<q^2<16{\text{GeV}}^2$. The results are among the most precise experimental measurements of the angular observables for this decay and are compared to a variety of predictions based on the standard model. Some of these predictions exhibit tension with the measurements.

Astrophys. J.

Recent observations of the Galactic component of the high-energy neutrino flux, together with the detection of the diffuse Galactic gamma-ray emission up to sub-PeV energies, open new possibilities to study the acceleration and propagation of cosmic rays in the Milky Way. At the same time, both large nonastrophysical backgrounds at TeV energies and the scarcity of neutrino events in the sub-PeV band currently limit these analyses. Here, we use the sample of cascade events with estimated neutrino energies above 200 TeV, detected by the partially deployed Baikal Gigaton Volume Detector (GVD) in 6 yr of operation, to test the continuation of the Galactic neutrino spectrum to sub-PeV energies. We find that the distribution of the arrival directions of Baikal-GVD cascades above 200 TeV in the sky suggests an excess of neutrinos from low Galactic latitudes with the chance probability of 1.4 × 10$^{−2}$. We also find the excess above 200 TeV in the most recent IceCube public data sets, both of cascades and tracks. The chance probability of the excess in the combined IceCube and Baikal-GVD analysis is 3.4 × 10$^{−4}$. The flux of Galactic neutrinos above 200 TeV challenges often-used templates for neutrino search based on cosmic-ray simulations.

Phys. Part. Nucl.

This brief review is based on a lecture given by one of the authors at the international youth conference AYSS-2023. It is devoted to multimessenger astronomy, which studies astrophysical objects and phenomena using various particles and waves that bring information from space. The messengers include electromagnetic and gravitational waves, neutrinos, and cosmic rays. We discuss new opportunities that open up with the combined use of several carriers of information. Combination of data obtained through various observation channels allows one to obtain more complete and accurate information about the processes occurring in the Universe, and even to use it for studying fundamental physics.

JHEP

Based on (2712.4 ± 14.3) × 10$^{6}$ψ(3686) events collected at the BESIII detector operating at the BEPCII collider, we present the first observation of the decay $\psi (3686)\to {K}^{-}\Lambda (1520){\overline{\Xi}}^{+}$ + c.c.. The product branching fraction $\mathcal{B}\left[\psi (3686)\to {K}^{-}\Lambda (1520){\overline{\Xi}}^{+}+\textrm{c}.\textrm{c}.\right]\times \mathcal{B}\left[\Lambda (1520)\to p{K}^{-}\right]$ is measured to be (9.47 ± 0.75 ± 0.97) × 10$^{−7}$, where the first uncertainty is statistical and the second systematic.[graphic not available: see fulltext]

JHEP

The first measurement of ϕ(1020) meson production in fixed-target pNe collisions at $\sqrt{s_{NN}}$ = 68.5 GeV is presented. The ϕ(1020) mesons are reconstructed in their K$^{+}$K$^{−}$ decay in a data sample consisting of proton collisions on neon nuclei at rest, corresponding to an integrated luminosity of 21.7 ± 1.4 nb$^{−1}$, collected by the LHCb detector at CERN. The ϕ(1020) production cross-section in the centre-of-mass rapidity range of −1.8 < y$^{*}$< 0 and transverse momentum range of 800 < p$_{T}$< 6500 MeV/c is found to be σ = 182.7 ± 2.7 (stat.) ± 14.1 (syst) μb/nucleon. A double-differential measurement of the cross-section is also provided in four regions of rapidity and six regions of transverse momentum of the ϕ(1020) meson and compared with the predictions from Pythia and EPOS4, which are found to underestimate the experimental values.[graphic not available: see fulltext]

JHEP

An analysis of the flavour oscillations of the charmed neutral meson is presented. The ratio of D$^{0}$ → K$^{+}$π$^{−}$ and D$^{0}$ → K$^{−}$π$^{+}$ decay rates is measured as a function of the decay time of the D$^{0}$ meson and compared with the charge-conjugated system to search for charge-parity violation. The meson flavour at production is double-tagged by the charges of the muon and pion in the preceding $\overline{B}\to {D}^{\ast }{(2010)}^{+}{\mu}^{-}X$ and D$^{∗}$(2010)$^{+}$ → D$^{0}$π$^{+}$ decays, respectively. These decays are selected from proton-proton collision data collected by the LHCb experiment at a centre-of-mass energy of 13 TeV and corresponding to an integrated luminosity of 5.4 fb$^{−1}$. The flavour oscillation parameters, relating to the differences in mass and width of the mass eigenstates, are found to be y′ = (5.8 ± 1.6) × 10$^{−3}$ and (x′)$^{2}$ = (0.0 ± 1.2) × 10$^{−4}$. No evidence for charge-parity violation is seen either in the flavour oscillations or in the decay, where the direct charge-parity asymmetry is measured to be A$_{D}$ = (2.3 ± 1.7) %.[graphic not available: see fulltext]

JHEP

A measurement of the CP-violating parameters in ${B}_s^0\boldsymbol{\to}{D}_s^{\mp }{K}^{\pm}$ decays is reported, based on the analysis of proton-proton collision data collected by the LHCb experiment corresponding to an integrated luminosity of 6 fb$^{−1}$ at a centre-of-mass energy of 13 TeV. The measured parameters are obtained with a decay-time dependent analysis yielding C$_{f}$ = 0.791 ± 0.061 ± 0.022, ${A}_f^{\Delta \Gamma}$ = −0.051 ± 0.134 ± 0.058, ${A}_{\overline{f}}^{\Delta \Gamma}$ = −0.303 ± 0.125 ± 0.055, S$_{f}$ = −0.571 ± 0.084 ± 0.023 and ${S}_{\overline{f}}$ = −0.503 ± 0.084 ± 0.025, where the first uncertainty is statistical and the second systematic. This corresponds to CP violation in the interference between mixing and decay of about 8.6 σ. Together with the value of the ${B}_s^0$ mixing phase −2β$_{s}$, these parameters are used to obtain a measurement of the CKM angle γ equal to (74 ± 12)° modulo 180°, where the uncertainty contains both statistical and systematic contributions. This result is combined with the previous LHCb measurement in this channel using 3 fb$^{−1}$ resulting in a determination of $\gamma ={\left({81}_{-11}^{+12}\right)}^{\circ }$.[graphic not available: see fulltext]

Phys. Rev. Lett.

Nuclear medium effects on $B^{+}$ meson production are studied using the binary-collision scaled cross section ratio between events of different charged-particle multiplicities from proton-lead collisions. Data, collected by the CMS experiment in 2016 at a nucleon-nucleon center-of-mass energy of $\sqrt{s_{\mathrm{NN}}}=8.16\mathrm{TeV}$, corresponding to an integrated luminosity of $175{\mathrm{nb}}^{-1}$, were used. The scaling factors in the ratio are determined using a novel approach based on the $Z\to {\mu }^{-}{\mu }^{+}$ cross sections measured in the same events. The scaled ratio for $B^{+}$ is consistent with unity for all event multiplicities, putting stringent constraints on nuclear modification for heavy flavor.

Phys. Rev. Lett.

Using $20.3{\mathrm{fb}}^{-1}$ of $e^{+}{e}^{-}$ collision data collected at the center-of-mass energy 3.773 GeV with the BESIII detector, we report the first observation of the semileptonic decay $D^{+}\to {\eta }^{\prime }{\mu }^{+}{\nu }_{\mu }$ with significance of $8.6\sigma$ including systematic uncertainties, and an improved measurement of $D^{+}\to {\eta }^{\prime }{e}^{+}{\nu }_e$. The branching fractions of $D^{+}\to {\eta }^{\prime }{\mu }^{+}{\nu }_{\mu }$ and $D^{+}\to {\eta }^{\prime }{e}^{+}{\nu }_e$ are determined to be $(1.92\pm 0.28_{\mathrm{stat}}\pm 0.08_{\mathrm{syst}})\times {10}^{-4}$ and $(1.79\pm 0.19_{\mathrm{stat}}\pm 0.07_{\mathrm{syst}})\times {10}^{-4}$, respectively. The ratio of the two branching fractions is determined to be ${\mathcal{R}}_{\mu /e}=1.07\pm 0.19_{\mathrm{stat}}\pm 0.03_{\mathrm{syst}}$, which agrees with the theoretical expectation of lepton flavor universality within the standard model. From an analysis of the $D^{+}\to {\eta }^{\prime }{\ell }^{+}{\nu }_{\ell }$ decay dynamics, the product of the hadronic form factor $f_{+}^{{\eta }^{\prime }}(0)$ and the Cabibbo-Kobayashi-Maskawa matrix element $|V_{cd}|$ is measured for the first time, giving $f_{+}^{{\eta }^{\prime }}(0)|V_{cd}|=(5.92\pm 0.56_{\mathrm{stat}}\pm 0.13_{\mathrm{syst}})\times {10}^{-2}$. The $\eta -{\eta }^{\prime }$ mixing angle in the quark flavor basis is determined to be ${\varphi }_{\mathrm{P}}=(39.8\pm {0.8}_{\mathrm{stat}}\pm {0.3}_{\mathrm{syst}})°$.

JHEP

A standard model effective field theory (SMEFT) analysis with dimension-six operators probing nonresonant new physics effects is performed in the Higgs-strahlung process, where the Higgs boson is produced in association with a W or Z boson, in proton-proton collisions at a center-of-mass energy of 13 TeV. The final states in which the W or Z boson decays leptonically and the Higgs boson decays to a pair of bottom quarks are considered. The analyzed data were collected by the CMS experiment between 2016 and 2018 and correspond to an integrated luminosity of 138 fb$^{−1}$. An approach designed to simultaneously optimize the sensitivity to Wilson coefficients of multiple SMEFT operators is employed. Likelihood scans as functions of the Wilson coefficients that carry SMEFT sensitivity in this final state are performed for different expansions in SMEFT. The results are consistent with the predictions of the standard model.[graphic not available: see fulltext]

Phys.Rev.Lett.

A study of ${\mathrm{\Lambda }}_b^0$ and ${\mathrm{\Xi }}_b^0$ decays to $\mathrm{\Lambda }{h}^{+}{h}^{\prime -}$ ($h^{(\prime )}=\pi ,K$) is performed using $pp$ collision data collected by the LHCb experiment during LHC Runs 1–2, corresponding to an integrated luminosity of $9{\mathrm{fb}}^{-1}$. The branching fractions for these decays are measured using the ${\mathrm{\Lambda }}_b^0\to {\mathrm{\Lambda }}_c^{+}(\to \mathrm{\Lambda }{\pi }^{+}){\pi }^{-}$ decay as a control channel. The decays ${\mathrm{\Lambda }}_b^0\to \mathrm{\Lambda }{\pi }^{+}{\pi }^{-}$ and ${\mathrm{\Xi }}_b^0\to \mathrm{\Lambda }{K}^{-}{\pi }^{+}$ are observed for the first time. For decay modes with sufficient signal yields, $CP$ asymmetries are measured in the full and localized regions of the final-state phase space. Evidence is found for $CP$ violation in the ${\mathrm{\Lambda }}_b^0\to \mathrm{\Lambda }{K}^{+}{K}^{-}$ decay, interpreted as originating primarily from an asymmetric ${\mathrm{\Lambda }}_b^0\to N^{*+}{K}^{-}$ decay amplitude. The measured $CP$ asymmetries for other decays are compatible with zero.

Phys. Rev. Lett.

The $CP$ asymmetry and branching fraction of the Cabibbo-Kobayashi-Maskawa-suppressed decay $B^{+}\to J/\psi {\pi }^{+}$ are precisely measured relative to the favored decay $B^{+}\to J/\psi K^{+}$ using a sample of proton-proton collision data corresponding to an integrated luminosity of $5.4{\mathrm{fb}}^{-1}$ recorded at a center-of-mass energy of 13 TeV during 2016–2018. The results of the $CP$ asymmetry difference and branching fraction ratio are $\mathrm{\Delta }{\mathcal{A}}^{CP}\equiv {\mathcal{A}}^{CP}(B^{+}\to J/\psi {\pi }^{+})-{\mathcal{A}}^{CP}(B^{+}\to J/\psi K^{+})=(1.29\pm 0.49\pm 0.08)\times {10}^{-2}$, ${\mathcal{R}}_{\pi /K}\equiv [\mathcal{B}(B^{+}\to J/\psi {\pi }^{+})/\mathcal{B}(B^{+}\to J/\psi K^{+})]=(3.852\pm 0.022\pm 0.018)\times {10}^{-2}$, where the first uncertainties are statistical and the second are systematic. A combination with previous LHCb results based on data collected at 7 and 8 TeV in 2011 and 2012 yields $\mathrm{\Delta }{\mathcal{A}}^{CP}=(1.42\pm 0.43\pm 0.08)\times {10}^{-2}$ and ${\mathcal{R}}_{\pi /K}=(3.846\pm 0.018\pm 0.018)\times {10}^{-2}$. The combined $\mathrm{\Delta }{\mathcal{A}}^{CP}$ value deviates from zero by 3.2 standard deviations, providing the first evidence for direct $CP$ violation in the amplitudes of beauty decays to charmonium final states.

Phys. Rev. Lett.

An amplitude analysis of $B^{-}\to D^{-}{D}^0{K}_S^0$ decays is performed using proton-proton collision data, corresponding to an integrated luminosity of $9{\mathrm{fb}}^{-1}$, collected with the LHCb detector at center-of-mass energies of 7, 8, and 13 TeV. A resonant structure of spin-parity $0^{+}$ is observed in the $D^0{K}_S^0$ invariant-mass spectrum with a significance of $5.3\sigma$. The mass and width of the state, modeled with a Breit-Wigner line shape, are determined to be $2883\pm 11\pm 8\mathrm{MeV}/c^2$ and ${87}_{-47}^{+22}\pm 17\mathrm{MeV}$, respectively, where the first uncertainties are statistical and the second systematic. These properties and the quark content are consistent with those of the open-charm tetraquark candidate $T_{cs0}^{*}(2870{)}^0$ observed previously in the $D^{+}{K}^{-}$ final state of the $B^{-}\to D^{-}{D}^{+}{K}^{-}$ decay. This result confirms the existence of the $T_{cs0}^{*}(2870{)}^0$ state in a new decay mode. The $T_{cs1}^{*}(2900{)}^0$ state, reported in the $B^{-}\to D^{-}{D}^{+}{K}^{-}$ decay, is also searched for in the $D^0{K}_S^0$ invariant-mass spectrum of the $B^{-}\to D^{-}{D}^0{K}_S^0$ decay, without finding evidence for it.

JHEP

An angular analysis of the ${B}_s^0$→ ϕe$^{+}$e$^{−}$ decay is performed using the proton-proton collision dataset collected between 2011 and 2018 by the LHCb experiment, corresponding to an integrated luminosity of 9 fb$^{−1}$ at centre-of-mass energies of 7, 8 and 13 TeV. The analysis is performed in the very low dielectron invariant mass-squared region between 0.0009 and 0.2615 GeV$^{2}$/c$^{4}$. The longitudinal polarisation fraction of the ϕ meson is measured to be less than 11.5% at 90% confidence level. The ${A}_{\textrm{T}}^{\mathcal{R} eCP}$ observable, which is related to the lepton forward-backward asymmetry, is measured to be 0.116 ± 0.155 ± 0.006, where the first uncertainty is statistical and the second systematic. The transverse asymmetries, ${A}_{\textrm{T}}^{(2)}$ and ${A}_{\textrm{T}}^{\mathcal{I} mCP}$, which are sensitive to the virtual photon polarisation, are found to be −0.045 ± 0.235 ± 0.014 and 0.002 ± 0.247 ± 0.016, respectively. The results are consistent with Standard Model predictions.[graphic not available: see fulltext]

Eur.Phys.J.C

The ATLAS experiment has developed extensive software and distributed computing systems for Run 3 of the LHC. These systems are described in detail, including software infrastructure and workflows, distributed data and workload management, database infrastructure, and validation. The use of these systems to prepare the data for physics analysis and assess its quality are described, along with the software tools used for data analysis itself. An outlook for the development of these projects towards Run 4 is also provided.

Nucl.Instrum.Meth.A

We present results of our study devoted to the development of a time correction algorithm needed to precisely synchronize a free-running Rubidium atomic clock with the Coordinated Universal Time (UTC). This R&D is performed in view of the Hyper-Kamiokande (HK) experiment currently under construction in Japan, which requires a synchronization with UTC and between its different experimental sites with a precision better than $100\mathrm{ns}$. We use a Global Navigation Satellite System (GNSS) receiver to compare a PPS and a 10 MHz signal, generated by a free-running Rubidium clock, to the Global Positioning System (GPS) Time signal. We use these comparisons to correct the time series (time stamps) provided by the Rubidium clock signal. We fit the difference between Rubidium and GPS Time with polynomial functions of time over a certain integration time window to extract a correction of the Rubidium time stamps in offline or online mode. In online mode, the latest fit results are used for the correction until a new comparison to GPS Time becomes available. We show that with an integration time window of around $10^4$ seconds, we can correct the time stamps drift, caused by the frequency random walk noise and the deterministic frequency drift of the free running Rubidium clock, so that the time difference with respect to GPS Time stays within a $\pm 5\mathrm{ns}$ range in both offline or online correction mode. Presented results could be of interest for other experiments in the field of neutrino physics and multi-messenger astrophysics.