A search is performed for lepton-number-violating $B^-\to D^{(*)+}μ^-μ^-$ decays, using data collected by the LHCb experiment in proton-proton collisions at a center-of-mass energy of 13 TeV, corresponding to an integrated luminosity of 5.4 fb$^{-1}$. No significant signal is observed, and upper limits are set on the branching fractions, ${\cal B}(B^-\to D^{+}μ^-μ^-) < 4.6 \times 10^{-8}$ and ${\cal B}(B^-\to D^{*+}μ^-μ^-) < 5.9 \times 10^{-8}$, at the 95% confidence level.
Binned efficiencies across the Dalitz plane for $B^- \to D^{+} \mu^- \mu^-$ decay. Here $\mu_1^-$ and $\mu_2^-$ represent the two muons produced in the decay, and the index specifies their ordering in transverse momentum. Efficiencies are normalized to the average over the full simulated sample.
Binned efficiencies across the Dalitz plane for $B^- \to D^{*+} \mu^- \mu^-$ decay. Here $\mu_1^-$ and $\mu_2^-$ represent the two muons produced in the decay, and the index specifies their ordering in transverse momentum. Efficiencies are normalized to the average over the full simulated sample.
We present searches for light dark matter (DM) with masses 3-9 GeV/$c^2$ in the presence of coherent elastic neutrino-nucleus scattering (CE$ν$NS) from $^{8}$B solar neutrinos with the LUX-ZEPLIN experiment. This analysis uses a 5.7 tonne-year exposure with data collected between March 2023 and April 2025. In an energy range spanning 1-6 keV, we report no significant excess of events attributable to dark matter nuclear recoils, but we observe a significant signal from $^{8}$B CE$ν$NS interactions that is consistent with expectation. We set world-leading limits on spin-independent and spin-dependent-neutron DM-nucleon interactions for masses down to 5 GeV/$c^2$. In the no-dark-matter scenario, we observe a signal consistent with $^{8}$B CE$ν$NS events, corresponding to a $4.5σ$ statistical significance. This is the most significant evidence of $^{8}$B CE$ν$NS interactions and is enabled by robust background modeling and mitigation techniques. This demonstrates LZ's ability to detect rare signals at keV-scale energies.
90% CL WIMP SI cross sections, including sensitivities
90% CL WIMP SDn cross sections, including sensitivities and nuclear structure uncertainties
90% CL WIMP SDp cross sections, including sensitivities and nuclear structure uncertainties
The GlueX experiment at Jefferson Lab has observed $p\bar{p}$ and, for the first time, $Λ\barΛ$ and $p\barΛ$ photoproduction from a proton target at photon energies up to 11.6 GeV. The angular distributions are forward peaked for all produced pairs, consistent with Regge-like $t$-channel exchange. Asymmetric wide-angle anti-baryon distributions show the presence of additional processes. In a phenomenological model, we find consistency with a double $t$-channel exchange process where anti-baryons are created only at the middle vertex. The model matches all observed distributions with a small number of free parameters. In the hyperon channels, we observe a clear distinction between photoproduction of the $Λ\barΛ$ and $p\barΛ$ systems but general similarity to the $p\bar{p}$ system. We report both total cross sections and cross sections differential with respect to momentum transfer and the invariant masses of the created particle pairs. No narrow resonant structures were found in these reaction channels. The suppression of $s\bar{s}$ quark pairs relative to $d\bar{d}$ quark pairs is similar to what has been seen in other reactions.
Measured $\frac{d\sigma}{dm_{\Lambda\bar{\Lambda}}}~[\mathrm{nb/GeV}]$ for reaction $\gamma p\to \{\Lambda \bar{\Lambda}\} p$ including data of $6.5 \leq E_{\gamma} \leq 11.5$ [GeV], splitted in 10 energy bins (each as a column in the table). The observable $m_{\Lambda\bar{\Lambda}}$ is in unit of $[\mathrm{nb/GeV}]$ and is divided into bins of width 0.05 $[\mathrm{GeV}]$ (each as a row in the table). The global systematic uncertainty is 19% (not included in the table), with contributions of 5% from kinematic fitting, 10% from data selection, 5% from flux normalization, 13% from tracking efficiency, 3% from model dependence, and 6% from run-period variations.
Measured $\frac{d\sigma}{dm_{p\bar{\Lambda}}}~[\mathrm{nb/GeV}]$ for reaction $\gamma p\to \{p \bar{\Lambda}\} \Lambda$ including data of $6.5 \leq E_{\gamma} \leq 11.5$ [GeV], splitted in 10 energy bins (each as a column in the table). The observable $m_{p\bar{\Lambda}}$ is in unit of $[\mathrm{nb/GeV}]$ and is divided into bins of width 0.1 $[\mathrm{GeV}]$ (each as a row in the table). The global systematic uncertainty is 22% (not included in the table), with contributions of 2% from kinematic fitting, 10% from data selection, 5% from flux normalization, 15% from tracking efficiency, 3% from model dependence, and 10% from run-period variations.
Measured $\frac{d\sigma}{dm_{p\bar{p}}}~[\mathrm{nb/GeV}]$ for reaction $\gamma p\to \{p \bar{p}\} p$ including data of $3.5 \leq E_{\gamma} \leq 11.5$ [GeV], splitted in 15 energy bins (each as a column in the table). The observable $m_{p\bar{p}}$ is in unit of $[\mathrm{nb/GeV}]$ and is divided into bins of width 0.044 $[\mathrm{GeV}]$ (each as a row in the table). The global systematic uncertainty is 13% (not included in the table), with contributions of 8% from kinematic fitting, 4% from data selection, 5% from flux normalization, 8% from tracking efficiency, 3% from model dependence, and 1% from run-period variations.
The $pp \to W^{\pm} (\to μ^{\pm} ν_μ) X$ cross-sections are measured at a proton-proton centre-of-mass energy $\sqrt{s} = 5.02$ TeV using a dataset corresponding to an integrated luminosity of 100 pb$^{-1}$ recorded by the LHCb experiment. Considering muons in the pseudorapidity range $2.2 < η< 4.4$, the cross-sections are measured differentially in twelve intervals of muon transverse momentum between $28 < p_\mathrm{T} < 52$ GeV. Integrated over $p_\mathrm{T}$, the measured cross-sections are \begin{align*} σ_{W^+ \to μ^+ ν_μ} &= 300.9 \pm 2.4 \pm 3.8 \pm 6.0~\text{pb}, \\ σ_{W^- \to μ^- \barν_μ} &= 236.9 \pm 2.1 \pm 2.7 \pm 4.7~\text{pb}, \end{align*} where the first uncertainties are statistical, the second are systematic, and the third are associated with the luminosity calibration. These integrated results are consistent with theoretical predictions. This analysis introduces a new method to determine the $W$-boson mass using the measured differential cross-sections corrected for detector effects. The measurement is performed on this statistically limited dataset as a proof of principle and yields \begin{align*} m_W = 80369 \pm 130 \pm 33~\text{MeV}, \end{align*} where the first uncertainty is experimental and the second is theoretical.
The measured differential cross sections ($d\sigma/dp_T$) for $W^+$. The first systematic uncertainty is statistical and the second is systematic.
The measured differential cross sections ($d\sigma/dp_T$) for $W^-$. The first systematic uncertainty is statistical and the second is systematic.
The correlation matrix corresponding to the statistical uncertainties on the differential cross-section ($d\sigma/dp_T$) fit results for $W^+$. To combine with $W^-$, use the rows and columns ordered as $W^+$ and then $W^-$. Assume no correlation in the statistical uncertainties between $W^+$ and $W^-$ (zero entries in the off-diagonal blocks).
The STAR experiment reports new, high-precision measurements of the transverse single-spin asymmetries for $π^{\pm}$ within jets, namely the Collins asymmetries, from transversely polarized ${p^{\uparrow}p}$ collisions at $\sqrt{s}$ = 510 GeV. The energy-scaled distribution of jet transverse momentum, $x_{\mathrm{T}} = 2p_{\mathrm{T,jet}}/\sqrt s$, shows a remarkable consistency for Collins asymmetries of $π^{\pm}$ in jets between $\sqrt{s}$ = 200 GeV and 510 GeV. This indicates that the Collins asymmetries are nearly energy independent with, at most, a very weak scale dependence in $p^{\uparrow}p$ collisions. These results extend to high-momentum scales ($Q^2 \leq 3400$ GeV$^2$) and enable unique tests of evolution and universality in the transverse-momentum-dependent formalism, thus providing important constraints for the Collins fragmentation functions.
Collins asymmetries, $A_{\mathrm{UT}}^{\sin(\phi_S - \phi_H)}$, as a function of jet $x_{\mathrm{T}}$ ($\equiv \frac{2p_{\mathrm{T,jet}}}{\sqrt{s}}$) for $\pi^{+}$ in $p^{\uparrow}p$ collisions at $\sqrt{s} = 510$ GeV. Vertical bars show the statistical uncertainties; boxes show the systematic uncertainties in $x_{\mathrm{T}}$ and $A_{\mathrm{UT}}$
Collins asymmetries, $A_{\mathrm{UT}}^{\sin(\phi_S - \phi_H)}$, as a function of jet $x_{\mathrm{T}}$ ($\equiv \frac{2p_{\mathrm{T,jet}}}{\sqrt{s}}$) for $\pi^{-}$ in $p^{\uparrow}p$ collisions at $\sqrt{s} = 510$ GeV. Vertical bars show the statistical uncertainties; boxes show the systematic uncertainties in $x_{\mathrm{T}}$ and $A_{\mathrm{UT}}
Collins asymmetries, $A_{\mathrm{UT}}^{\sin(\phi_S - \phi_H)}$, as a function of $\pi^{+}$ momentum fraction longitudinal momentum fraction $z$ in $p^{\uparrow}p$ collisions at $\sqrt{s} = 510$ GeV. Vertical bars show the statistical uncertainties; boxes show the systematic uncertainties.
We present a determination of the Cabibbo-Kobayashi-Maskawa matrix element $|V_{cb}|$ from the decay $B\to D\ellν_\ell$ using a $365~\mathrm{fb}^{-1}$$e^+e^-\toΥ(4S)\to B\bar B$ data sample recorded by the Belle II experiment at the SuperKEKB collider. The semileptonic decay of one $B$ meson is reconstructed in the modes $B^0\to D^-(\to K^+π^-π^-)\ell^+ν_\ell$ and $B^+\to \bar D^0(\to K^+π^-)\ell^+ν_\ell$, where $\ell$ denotes either an electron or a muon. Charge conjugation is implied. The second $B$ meson in the $Υ(4S)$ event is not reconstructed explicitly. Using an inclusive reconstruction of the unobserved neutrino momentum, we determine the recoil variable $w=v_B\cdot v_D$, where $v_B$ and $v_D$ are the 4-velocities of the $B$ and $D$ mesons. We measure the total decay branching fractions to be $\mathcal{B}(B^0\to D^-\ell^+ν_\ell)=(2.06 \pm 0.05\,(\mathrm{stat.}) \pm 0.10\,(\mathrm{sys.}))\%$ and $\mathcal{B}(B^+\to\bar D^0\ell^+ν_\ell)=(2.31 \pm 0.04\,(\mathrm{stat.}) \pm 0.09\,(\mathrm{sys.}))\%$. We probe lepton flavor universality by measuring $\mathcal{B}(B\to Deν_e)/\mathcal{B}(B\to Dμν_μ)=1.020 \pm 0.020\,(\mathrm{stat.})\pm 0.022\,(\mathrm{sys.})$. Fitting the partial decay branching fraction as a function of $w$ and using the average of lattice QCD calculations of the $B\to D$ form factor, we obtain $ |V_{cb}|=(39.2\pm 0.4\,(\mathrm{stat.}) \pm 0.6\,(\mathrm{sys.}) \pm 0.5\,(\mathrm{th.})) \times 10^{-3}$.
Differential decay rate $d\Gamma/dw$ for $B \to D \ell \nu$ averaged over 4 modes. The uncertainty listed represents the total uncertainty from statistical and systematic sources.
Differential decay rates $d\Gamma/dw$ for individual $B \to D \ell \nu$ modes. The uncertainty listed represents the total uncertainty from statistical and systematic sources.
Correlations (stat.+syst.) between the $d\Gamma_i/dw$ bins for the averaged $B \rightarrow D \ell \nu$ spectrum (10x10). Element indices 0-9 correspond to $w$ bins: 0: [1.00, 1.06], 1: [1.06, 1.12], 2: [1.12, 1.18], 3: [1.18, 1.24], 4: [1.24, 1.30], 5: [1.30, 1.36], 6: [1.36, 1.42], 7: [1.42, 1.48], 8: [1.48, 1.54], 9: [1.54, 1.59]
A study on the Bose-Einstein correlations for triplets of same-sign pions is presented. The analysis is performed using proton-proton collisions at a centre-of-mass energy of $\sqrt{s}$ = 7 TeV, recorded by the LHCb experiment, corresponding to an integrated luminosity of 1.0 fb$^{-1}$. For the first time, the results are interpreted in the core-halo model. The parameters of the model are determined in regions of charged-particle multiplicity. This measurement provides insight into the nature of hadronisation in terms of coherence, showing a coherent emission of pions.
Results of the fit to the three-particle double ratio ($r_{d_{3}}$) for same-sign pion triplets, VELO track multiplicity for pp collision: 5-10.
Results of the fit to the three-particle double ratio ($r_{d_{3}}$) for same-sign pion triplets, VELO track multiplicity for pp collision: 11-20.
Results of the fit to the three-particle double ratio ($r_{d_{3}}$) for same-sign pion triplets, VELO track multiplicity for pp collision: 21-60.
While dual-phase xenon time projection chambers (TPCs) have driven the sensitivity towards weakly interacting massive particles (WIMPs) at the GeV/c^2 to TeV/c^2 mass scale, the scope for sub-GeV/c^2 dark matter particles is hindered by a limited nuclear recoil energy detection threshold. One approach to probe for lighter candidates is to consider cases where they have been boosted by collisions with cosmic rays in the Milky Way, such that the additional kinetic energy lifts their induced signatures above the nominal threshold. In this Letter, we report first results of a search for cosmic ray-boosted dark matter (CRDM) with a combined 4.2 tonne-year exposure from the LUX-ZEPLIN (LZ) experiment. We observe no excess above the expected backgrounds and establish world-leading constraints on the spin-independent CRDM-nucleon cross section as small as 3.9 * 10^{-33} cm^2 at 90% confidence level for sub-GeV/c^2 masses.
90% CL CRDM-nucleon cross sections
The LHCb collaboration presents a novel suite of heavy-flavour jet substructure measurements at forward rapidity in proton-proton collisions at a centre-of-mass energy of $\sqrt{s} = 13$ TeV. The jet mass is a perturbatively calculable probe of the virtuality of hard-scattered quarks and gluons, connecting small-distance quantum chromodynamics (QCD) with long-distance experimental measurement. It becomes dominated by nonperturbative corrections at small values, presenting an excellent test of QCD across a broad range of energies. Measuring heavy-flavour jet mass with a theoretically unambiguous flavour definition for the first time probes the gluon splitting mechanism for heavy-flavour production and pushes tests of perturbative QCD to unprecedented theoretical precision. Utilising the soft drop jet-grooming technique to access the perturbative jet core further enhances constraints on first-principles theory. Measurements of the jet mass for jets containing fully reconstructed $B^\pm$ hadrons are reported with and without grooming. These results offer unparalleled tests of quark flavour and mass dependence in QCD and provide a baseline for future studies of heavy-flavour jet quenching in heavy-ion collisions.
Groomed $B^\pm$-tagged jet invariant mass $m_{\textrm{jet,gr}}/p_{\textrm{T,jet}}$ for $R=0.5$ jets reconstructed in pp data, without any WTA flavour requirement. Normalization is set to unity. $10 < p_{\textrm{T,jet}} < 12$ GeV, soft drop $z_{\textrm{cut}}=0.1, \beta=0$.
Groomed $B^\pm$-tagged jet invariant mass $m_{\textrm{jet,gr}}/p_{\textrm{T,jet}}$ for $R=0.5$ jets reconstructed in pp data, without any WTA flavour requirement. Normalization is set to unity. $12 < p_{\textrm{T,jet}} < 15$ GeV, soft drop $z_{\textrm{cut}}=0.1, \beta=0$.
Groomed $B^\pm$-tagged jet invariant mass $m_{\textrm{jet,gr}}/p_{\textrm{T,jet}}$ for $R=0.5$ jets reconstructed in pp data, without any WTA flavour requirement. Normalization is set to unity. $15 < p_{\textrm{T,jet}} < 20$ GeV, soft drop $z_{\textrm{cut}}=0.1, \beta=0$.
We present the results of a search for the charged-lepton-flavor violating decays $B^0 \rightarrow K^{*0}\tau^\pm \ell^{\mp}$, where $\ell^{\mp}$ is either an electron or a muon. The results are based on 365 fb$^{-1}$ and 711 fb$^{-1}$ datasets collected with the Belle II and Belle detectors, respectively. We use an exclusive hadronic $B$-tagging technique, and search for a signal decay in the system recoiling against a fully reconstructed $B$ meson. We find no evidence for $B^0 \rightarrow K^{*0}\tau^\pm \ell^{\mp}$ decays and set upper limits on the branching fractions in the range of $(2.9-6.4)\times10^{-5}$ at 90% confidence level.
$M_{\tau}$ distribution in signal region, (OS$e$, Belle)
$M_{\tau}$ distribution in signal region, (OS$e$, Belle II)
$M_{\tau}$ distribution in signal region, (OS$\mu$, Belle)
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