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Journal articleAbdalla A, Abe M, Abend S, et al., 2025,
Terrestrial Very-Long-Baseline Atom Interferometry: summary of the second workshop
, EPJ Quantum Technology, Vol: 12This summary of the second Terrestrial Very-Long-Baseline Atom Interferometry (TVLBAI) Workshop provides a comprehensive overview of our meeting held in London in April 2024 (Second Terrestrial Very-Long-Baseline Atom Interferometry Workshop, Imperial College, April 2024), building on the initial discussions during the inaugural workshop held at CERN in March 2023 (First Terrestrial Very-Long-Baseline Atom Interferometry Workshop, CERN, March 2023). Like the summary of the first workshop (Abend et al. in AVS Quantum Sci. 6:024701, 2024), this document records a critical milestone for the international atom interferometry community. It documents our concerted efforts to evaluate progress, address emerging challenges, and refine strategic directions for future large-scale atom interferometry projects. Our commitment to collaboration is manifested by the integration of diverse expertise and the coordination of international resources, all aimed at advancing the frontiers of atom interferometry physics and technology, as set out in a Memorandum of Understanding signed by over 50 institutions (Memorandum of Understanding for the Terrestrial Very Long Baseline Atom Interferometer Study).
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Journal articleLippincott WH, Nelson HN, Akerib DS, et al., 2025,
HydroX, a light dark matter search with hydrogen-doped liquid xenon time projection chambers
, Communications Physics, Vol: 8Experimental efforts searching for dark matter particles over the last few decades have ruled out many candidates led by the new generation of tonne-scale liquid xenon. For light dark matter, hydrogen could be a better target than xenon as it would offer a better kinematic match to the low mass particles. This article describes the HydroX concept, an idea to expand the dark matter sensitivity reach of large liquid xenon detectors by adding hydrogen to the liquid xenon. We discuss the nature of signal generation in liquid xenon to argue that the signal produced at the interaction site by a dark matter–hydrogen interaction could be significantly enhanced over the same interaction on xenon, increasing the sensitivity to the lightest particles. We discuss the technical implications of adding hydrogen to a xenon detector, as well as some background considerations. Finally, we make projections as to the potential sensitivity of a HydroX implementation and discuss next steps.
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Journal articleDas K, Karikar A, Mazumdar D, et al., 2025,
Study of magnetic and magnetocaloric properties of polycrystalline Pr0.6Ca0.4MnO3 compound
, Journal of Magnetism and Magnetic Materials, Vol: 628, ISSN: 0304-8853The magnetic and magnetocaloric properties of chemically single-phase polycrystalline Pr<inf>0.6</inf>Ca<inf>0.4</inf>MnO<inf>3</inf> compound have been systematically investigated. The compound exhibits a sequence of complex magnetic transitions with decreasing temperature, including charge ordering phenomenon around T<inf>CO</inf>∼240 K and antiferromagnetic ordering at T∼170 K. At lower temperatures, a canted antiferromagnetic state emerges (T<50 K), significantly influencing the magnetocaloric response. The instability of the antiferromagnetic phase and the nucleation of ferromagnetic regions make the magnetic state highly sensitive to external perturbations, particularly in the low-temperature regime. Furthermore, an anomalous behavior in the metamagnetic transition field has been observed at low temperatures, highlighting the intricate nature of the magnetic interactions in this system.
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Journal articleChekhovsky V, Hayrapetyan A, Makarenko V, et al., 2025,
Determination of the strong coupling and its running from measurements of inclusive jet production
, Physics Letters Section B Nuclear Elementary Particle and High Energy Physics, Vol: 868, ISSN: 0370-2693The value of the strong coupling α<inf>S</inf> is determined in a comprehensive analysis at next-to-next-to-leading order accuracy in quantum chromodynamics. The analysis uses double-differential cross section measurements from the CMS Collaboration at the CERN LHC of inclusive jet production in proton-proton collisions at centre-of-mass energies of 2.76, 7, 8, and 13 TeV, combined with inclusive deep-inelastic data from HERA. The value α<inf>S</inf>(m<inf>Z</inf>)=0.1176<inf>−0.0016</inf><sup>+0.0014</sup> is obtained at the scale of the Z boson mass. By using the measurements in different intervals of jet transverse momentum, the running of α<inf>S</inf> is probed for energies between 100 and 1600 GeV.
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Journal articleHayrapetyan A, Tumasyan A, Adam W, et al., 2025,
Search for heavy neutral Higgs bosons A and H in the tt¯Z channel in proton-proton collisions at 13 TeV
, Physics Letters Section B Nuclear Elementary Particle and High Energy Physics, Vol: 866, ISSN: 0370-2693A direct search for new heavy neutral Higgs bosons [Figure presented] and [Figure presented] in the [Figure presented] channel is presented, targeting the process [Figure presented] with [Figure presented]. For the first time, the channel with decays of the [Figure presented] boson to muons or electrons in association with all-hadronic decays of the [Figure presented] system is targeted. The analysis uses proton-proton collision data collected at the CERN LHC with the CMS experiment at s=13TeV, which correspond to an integrated luminosity of 138fb<sup>−1</sup>. No signal is observed. Upper limits on the product of the cross section and branching fractions are derived for narrow resonances [Figure presented] and [Figure presented] with masses up to 2100 and 2000 GeV, respectively, assuming [Figure presented] boson production through gluon fusion. The results are also interpreted within two-Higgs-doublet models, where [Figure presented] and [Figure presented] are CP-odd and CP-even states, respectively, complementing and substantially extending the reach of previous searches.
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Journal articleHayrapetyan A, Tumasyan A, Adam W, et al., 2025,
Measurement of the Drell–Yan forward-backward asymmetry and of the effective leptonic weak mixing angle in proton-proton collisions at s=13TeV
, Physics Letters Section B Nuclear Elementary Particle and High Energy Physics, Vol: 866, ISSN: 0370-2693The forward-backward asymmetry in Drell–Yan production and the effective leptonic electroweak mixing angle are measured in proton-proton collisions at s=13 TeV, collected by the CMS experiment and corresponding to an integrated luminosity of 138fb<sup>−1</sup>. The measurement uses both dimuon and dielectron events, and is performed as a function of the dilepton mass and rapidity. The unfolded angular coefficient A<inf>4</inf> is also extracted, as a function of the dilepton mass and rapidity. Using the CT18Z set of parton distribution functions, we obtain sin<sup>2</sup>θ<inf>eff</inf><sup>ℓ</sup>=0.23152±0.00031, where the uncertainty includes the experimental and theoretical contributions. The measured value agrees with the standard model fit result to global experimental data. This is the most precise sin<sup>2</sup>θ<inf>eff</inf><sup>ℓ</sup> measurement at a hadron collider, with a precision comparable to the results obtained at LEP and SLD.
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Journal articleChekhovsky V, Hayrapetyan A, Makarenko V, et al., 2025,
Observation of nuclear modification of energy-energy correlators inside jets in heavy ion collisions
, Physics Letters Section B Nuclear Elementary Particle and High Energy Physics, Vol: 866, ISSN: 0370-2693Energy-energy correlators are constructed by averaging the number of charged particle pairs within jets, weighted by the product of their transverse momenta, as a function of the angular separation of the particles within a pair. They are sensitive to a multitude of perturbative and nonperturbative quantum chromodynamics phenomena in high-energy particle collisions. Using lead-lead data recorded with the CMS detector, energy-energy correlators inside high transverse momentum jets are measured in heavy ion collisions for the first time. The data are obtained at a nucleon-nucleon center-of-mass energy of 5.02 TeV and correspond to an integrated luminosity of 1.70nb<sup>−1</sup>. A similar analysis is done for proton-proton collisions at the same center-of-mass energy to establish a reference. The ratio of lead-lead to proton-proton energy-energy correlators reveals significant jet substructure modifications in the quark-gluon plasma. The results are compared to different models that incorporate either color coherence or medium response effects, where the two effects predict similar substructure modifications.
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Journal articleAaij R, Abdelmotteleb ASW, Abellan Beteta C, et al., 2025,
Search for the Bc+→ χc1(3872)π+ decay
, Journal of High Energy Physics, Vol: 2025A search for the decay Bc+→ χ<inf>c1</inf>(3872)π<sup>+</sup> is reported using proton-proton collision data collected with the LHCb detector between 2011 and 2018 at centre-of-mass energies of 7, 8, and 13 TeV, corresponding to an integrated luminosity of 9 fb<sup>−1</sup>. No significant signal is observed. Using the decay Bc+ → ψ(2S)π<sup>+</sup> as a normalisation channel, an upper limit for the ratio of branching fractions (Formula presented.) is set at the 90 (95)% confidence level.
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Journal article, 2025,
Model-agnostic search for dijet resonances with anomalous jet substructure in proton–proton collisions at <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:msqrt> <mml:mi>s</mml:mi> </mml:msqrt> </mml:mrow> </mml:math> = 13 TeV
, Reports on Progress in Physics, Vol: 88, Pages: 067802-067802, ISSN: 0034-4885<jats:title>Abstract</jats:title> <jats:p>This paper presents a model-agnostic search for narrow resonances in the dijet final state in the mass range 1.8–6 TeV. The signal is assumed to produce jets with substructure atypical of jets initiated by light quarks or gluons, with minimal additional assumptions. Search regions are obtained by utilizing multivariate machine-learning methods to select jets with anomalous substructure. A collection of complementary anomaly detection methods—based on unsupervised, weakly supervised, and semisupervised algorithms—are used in order to maximize the sensitivity to unknown new physics signatures. These algorithms are applied to data corresponding to an integrated luminosity of 138 fb<jats:sup>−1</jats:sup>, recorded by the CMS experiment at the LHC, at a center-of-mass energy of 13 TeV. No significant excesses above background expectations are seen. Exclusion limits are derived on the production cross section of benchmark signal models varying in resonance mass, jet mass, and jet substructure. Many of these signatures have not been previously sought, making several of the limits reported on the corresponding benchmark models the first ever. When compared to benchmark inclusive and substructure-based search strategies, the anomaly detection methods are found to significantly enhance the sensitivity to a variety of models.</jats:p>
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Journal articleHayrapetyan A, Tumasyan A, Adam W, et al., 2025,
Search for rare decays of the Z and Higgs bosons to a J/ψ or ψ(2S) meson and a photon in proton-proton collisions at s=13TeV
, Physics Letters Section B Nuclear Elementary Particle and High Energy Physics, Vol: 865, ISSN: 0370-2693A search is presented for rare decays of the [Figure presented] and Higgs bosons to a photon and a [Figure presented] or a [Figure presented] meson, with the charmonium state subsequentially decaying to a pair of muons. The data set corresponds to an integrated luminosity of 123fb<sup>−1</sup> of proton-proton collisions at a center-of-mass energy of 13 TeV collected with the CMS detector at the LHC. No evidence for branching fractions of these rare decay channels larger than predicted in the standard model is observed. Upper limits at 95% confidence level are set: [Figure presented], [Figure presented], [Figure presented], and [Figure presented]. The ratio of the Higgs boson coupling modifiers [Figure presented] is constrained to be in the interval (−157,+199) at 95% confidence level. Assuming [Figure presented], this interval becomes (−166,+208).
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Journal articlePal K, Mandal S, Dey S, et al., 2025,
Unraveling the origins of exchange bias and magnetic anomalies in Sr2FeRuO6: Experimental and theoretical insights
, Materials Today Communications, Vol: 46Interactions in strongly correlated magnetic systems are critical to the emergence of unconventional magnetic phenomena. In this work, we combine experimental and theoretical methods to investigate the mixed 3d–4d double perovskite Sr<inf>2</inf>FeRuO<inf>6</inf>, which exhibits rich and complex magnetic behavior. Structural and microstructural features were characterized using X-ray diffraction and transmission electron microscopy, while magnetization studies under zero-field-cooled and field-cooled protocols were conducted to probe the magnetic response. Complementary Monte Carlo simulations were performed to elucidate the underlying spin dynamics and interaction landscape. Our comprehensive analysis reveals that antisite disorder and the competition between ferromagnetic, antiferromagnetic, and spin-glass-like interactions give rise to exchange bias and other anomalous magnetic features. These results establish Sr<inf>2</inf>FeRuO<inf>6</inf> as a model system for exploring frustration-driven magnetism in complex oxides.
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Journal articleAaij R, Abdelmotteleb ASW, Beteta CA, et al., 2025,
Study of D<inf>s1</inf>(2460)<sup>+</sup>→D<inf>s</inf><sup>+</sup>π<sup>+</sup>π<sup>-</sup> in B→D‾<sup>(*)</sup>D<inf>s</inf><sup>+</sup>π<sup>+</sup>π<sup>-</sup> decays
, Science Bulletin, Vol: 70, Pages: 1432-1444, ISSN: 2095-9273An amplitude analysis of the Ds1(2460)+→Ds+π+π- transition is performed simultaneously in B0→D-Ds+π+π-, B+→D‾0Ds+π+π-, and B0→D*-Ds+π+π- decays. The study is based on a data sample of proton-proton collisions recorded with the LHCb detector at centre-of-mass energies of s=7,8, and 13 TeV, corresponding to a total integrated luminosity of 9fb-1. A clear double-peak structure is observed in the m(π+π-) spectrum of the Ds1(2460)+→Ds+π+π- decay. The data can be described either with a model including f0500,f0980, and f2(1270) resonances, in which the contributions of f0(980) and f2(1270) are unexpectedly large, or with a model including f0(500), a doubly charged open-charm tetraquark state Tcs¯++ and its isospin partner Tcs¯0. If the former is considered implausible, the Tcs¯ states are observed with high significance, and the data are consistent with isospin symmetry. When imposing isospin constraints between the two Tcs¯ states, their mass and width are determined to be (2327±13±13) MeV and (96±16-23+170) MeV, respectively, where the first uncertainty is statistical and the second is systematic. The mass is slightly below the DK threshold, and a spin-parity of 0+ is favoured with high significance.
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Journal articleAbed Abud A, Abi B, Acciarri R, et al., 2025,
Supernova pointing capabilities of DUNE
, Physical Review D, Vol: 111, ISSN: 2470-0010<jats:p>The determination of the direction of a stellar core collapse via its neutrino emission is crucial for the identification of the progenitor for a multimessenger follow-up. A highly effective method of reconstructing supernova directions within the Deep Underground Neutrino Experiment (DUNE) is introduced. The supernova neutrino pointing resolution is studied by simulating and reconstructing electron-neutrino charged-current absorption on <a:math xmlns:a="http://www.w3.org/1998/Math/MathML" display="inline"><a:mrow><a:mmultiscripts><a:mrow><a:mi>Ar</a:mi></a:mrow><a:mprescripts/><a:none/><a:mrow><a:mn>40</a:mn></a:mrow></a:mmultiscripts></a:mrow></a:math> and elastic scattering of neutrinos on electrons. Procedures to reconstruct individual interactions, including a newly developed technique called “brems flipping,” as well as the burst direction from an ensemble of interactions are described. Performance of the burst direction reconstruction is evaluated for supernovae happening at a distance of 10 kpc for a specific supernova burst flux model. The pointing resolution is found to be 3.4 degrees at 68% coverage for a perfect interaction-channel classification and a fiducial mass of 40 kton, and 6.6 degrees for a 10 kton fiducial mass respectively. Assuming a 4% rate of charged-current interactions being misidentified as elastic scattering, DUNE’s burst pointing resolution is found to be 4.3 degrees (8.7 degrees) at 68% coverage.</jats:p> <jats:sec> <jats:title/> <jats:supplementary-material> <jats:permissions> <jats:copyright-statement>Published by the American Physical Society</jats:copyright-statement> <jats:copyright-year>2025</jats:copyright-year>
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Journal articleAaij R, Abdelmotteleb ASW, Abellan Beteta C, et al., 2025,
Test of Lepton Flavor Universality with B+ →k+π+π-ℓ+ℓ- Decays
, Physical Review Letters, Vol: 134, ISSN: 0031-9007The first test of lepton flavor universality between muons and electrons using B+→K+π+π-ℓ+ℓ- (ℓ=e, μ) decays is presented. The measurement is performed with data from proton-proton collisions collected by the LHCb experiment at center-of-mass energies of 7, 8, and 13 TeV, corresponding to an integrated luminosity of 9 fb-1. The ratio of branching fractions between B+→K+π+π-e+e- and B+→K+π+π-μ+μ- decays is measured in the dilepton invariant-mass-squared range 1.1<q2<7.0 GeV2/c4 and is found to be RKππ-1=1.31-0.17+0.18(stat) -0.09+0.12(syst), in agreement with the standard model prediction. The first observation of the B+→K+π+π-e+e- decay is also reported.
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Journal articleChekhovsky V, Hayrapetyan A, Makarenko V, et al., 2025,
Measurements of the Higgs boson production cross section in the four-lepton final state in proton-proton collisions at $$\sqrt{s}$$ = 13.6 TeV
, Journal of High Energy Physics, Vol: 2025<jats:title>A<jats:sc>bstract</jats:sc> </jats:title> <jats:p>The measurements of the Higgs boson (H) production cross sections performed by the CMS Collaboration in the four-lepton (4<jats:italic>ℓ, ℓ</jats:italic> = e<jats:italic>,</jats:italic> μ) final state at a center-of-mass energy <jats:inline-formula> <jats:tex-math>$$\sqrt{s}$$</jats:tex-math> </jats:inline-formula> = 13<jats:italic>.</jats:italic>6 TeV are presented. These measurements are based on data collected with the CMS detector at the CERN LHC in 2022, corresponding to an integrated luminosity of 34.7 fb<jats:sup> <jats:italic>−</jats:italic>1</jats:sup>. Cross sections are measured in a fiducial region closely matching the experimental acceptance, both inclusively and differentially, as a function of the transverse momentum and the absolute value of the rapidity of the four-lepton system. The H → ZZ → 4<jats:italic>ℓ</jats:italic> inclusive fiducial cross section is measured to be <jats:inline-formula> <jats:tex-math>$${2.89}_{-0.49}^{+0.53}{\left({\text{stat}}\right)}_{-0.21}^{+0.29}\left({\text{syst}}\right)$$</jats:tex-math> </jats:inline-formula> fb, in agreement with the standard model expectation of <jats:inline-formula> <jats:tex-math>$${3.09}_{-0.24}^{+0.27}$$</jats:tex-math> </jats:inline-formula> fb.</jats:p>
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Journal articleHayrapetyan A, Tumasyan A, Adam W, et al., 2025,
Reweighting simulated events using machine-learning techniques in the CMS experiment
, The European Physical Journal C, Vol: 85<jats:title>Abstract</jats:title> <jats:p>Data analyses in particle physics rely on an accurate simulation of particle collisions and a detailed simulation of detector effects to extract physics knowledge from the recorded data. Event generators together with a <jats:sc>geant</jats:sc>-based simulation of the detectors are used to produce large samples of simulated events for analysis by the LHC experiments. These simulations come at a high computational cost, where the detector simulation and reconstruction algorithms have the largest CPU demands. This article describes how machine-learning (ML) techniques are used to reweight simulated samples obtained with a given set of parameters to samples with different parameters or samples obtained from entirely different simulation programs. The ML reweighting method avoids the need for simulating the detector response multiple times by incorporating the relevant information in a single sample through event weights. Results are presented for reweighting to model variations and higher-order calculations in simulated top quark pair production at the LHC. This ML-based reweighting is an important element of the future computing model of the CMS experiment and will facilitate precision measurements at the High-Luminosity LHC.</jats:p>
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Journal articleAaij R, Abdelmotteleb ASW, Abellan Beteta C, et al., 2025,
Search for D0 meson decays to π+π-e+e- and K+K-e+e- final states
, Physical Review D, Vol: 111, ISSN: 2470-0010A search for D0 meson decays to the π+π-e+e- and K+K-e+e- final states is reported using a sample of proton-proton collisions collected by the LHCb experiment at a center-of-mass energy of 13 TeV, corresponding to an integrated luminosity of 6 fb-1. The decay D0→π+π-e+e- is observed for the first time when requiring that the two electrons are consistent with coming from the decay of a φ or ρ0/ω meson. The corresponding branching fractions are measured relative to the D0→K-π-[e+e-]ρ0/ω decay, where the two electrons are consistent with coming from the decay of a ρ0 or ω meson. No evidence is found for the D0→K+K-e+e- decay and world-best limits are set on its branching fraction. The results are compared to, and found to be consistent with, the branching fractions of the D0→π+π-μ+μ- and D0→K+K-μ+μ- decays recently measured by LHCb and confirm lepton universality at the current precision.
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Journal articleHayrapetyan A, Tumasyan A, Adam W, et al., 2025,
Angular analysis of the B0 → K⁎(892)0μ+μ− decay in proton-proton collisions at s=13TeV
, Physics Letters Section B Nuclear Elementary Particle and High Energy Physics, Vol: 864, ISSN: 0370-2693A full set of optimized observables is measured in an angular analysis of the decay B<sup>0</sup>→K<sup>⁎</sup>(892)<sup>0</sup>μ<sup>+</sup>μ<sup>−</sup> using a sample of proton-proton collisions at s=13TeV, collected with the CMS detector at the LHC, corresponding to an integrated luminosity of 140 fb<sup>−1</sup>. The analysis is performed in six bins of the squared invariant mass of the dimuon system, q<sup>2</sup>, over the range 1.1<q<sup>2</sup><16GeV<sup>2</sup>. 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.
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Journal articleAaij R, Abdelmotteleb ASW, Abellan Beteta C, et al., 2025,
Search for resonance-enhanced (Formula presented) and angular asymmetries in the (Formula presented) decay at LHCb
, Physical Review D, Vol: 111, ISSN: 2470-0010The first measurement of the (Formula presented) asymmetry of the decay rate ((Formula presented)) and the (Formula presented) average ((Formula presented)) and (Formula presented) asymmetry ((Formula presented)) of the forward-backward asymmetry in the muon system of (Formula presented) decays is reported. The measurement is performed using a data sample of proton-proton collisions, recorded by the LHCb experiment from 2016 to 2018 at a center-of-mass energy of 13 TeV, which corresponds to an integrated luminosity of (Formula presented). The asymmetries are measured in two regions of dimuon mass near the (Formula presented)-meson mass peak. The dimuon-mass integrated results are (Formula presented), (Formula presented), (Formula presented), where the first uncertainty is statistical and the second systematic. The results are consistent with the conservation of (Formula presented) symmetry and the Standard Model expectations.
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Journal articleHayrapetyan A, Tumasyan A, Adam W, et al., 2025,
Measurement of the Higgs boson mass and width using the four-lepton final state in proton-proton collisions at (Formula presented)
, Physical Review D, Vol: 111, ISSN: 2470-0010A measurement of the Higgs boson mass and width via its decay to two (Formula presented) bosons is presented. Proton-proton collision data collected by the CMS experiment, corresponding to an integrated luminosity of (Formula presented) at a center-of-mass energy of 13 TeV, is used. The invariant mass distribution of four leptons in the on-shell Higgs boson decay is used to measure its mass and constrain its width. This yields the most precise single measurement of the Higgs boson mass to date, (Formula presented), and an upper limit on the width (Formula presented) at 95% confidence level. A combination of the on- and off-shell Higgs boson production decaying to four leptons is used to determine the Higgs boson width, assuming that no new virtual particles affect the production, a premise that is tested by adding new heavy particles in the gluon fusion loop model. This result is combined with a previous CMS analysis of the off-shell Higgs boson production with decay to two leptons and two neutrinos, giving a measured Higgs boson width of (Formula presented), in agreement with the standard model prediction of 4.1 MeV. The strength of the off-shell Higgs boson production is also reported. The scenario of no off-shell Higgs boson production is excluded at a confidence level corresponding to 3.8 standard deviations.
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Journal articleAaij R, Abdelmotteleb ASW, Abellan Beteta C, et al., 2025,
Study of light-meson resonances decaying to K S0 Kπ in the B → (K S0 Kπ)K channels
, Physical Review D, Vol: 111, ISSN: 2470-0010A study is presented of B+→KS0K-π+K+ and B+→KS0K+π-K+ decays based on the analysis of proton-proton collision data collected with the LHCb detector at center-of-mass energies of 7, 8 and 13 TeV, corresponding to an integrated luminosity of 9 fb-1. The KS0Kπ invariant-mass distributions of both B+ decay modes show, in the m(KS0Kπ)<1.85 GeV mass region, large activity which is resolved using an amplitude analysis. A simple model, where JPC amplitudes are described by multiple Breit-Wigner functions with appropriate angular distributions, provides a good description of the experimental data. In this approach a complex mixture of JPC=0-+, 1++ and 1+- amplitudes is observed that is dominated by η(1405), η(1470), η(1760), f1(1285), f1(1420) and h1(1405) resonances. The KS0Kπ Dalitz plots are dominated by asymmetric crossing K∗K̄ bands which are different for the two B+ decay modes. This is due to a different interference pattern between the 1++ and 1+- amplitudes in the two channels. Branching fractions are measured for each resonant contribution.
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Journal articleAaij R, Abdelmotteleb ASW, Abellan Beteta C, et al., 2025,
Measurement of (Formula presented) asymmetries in (Formula presented) decays
, Physical Review D, Vol: 111, ISSN: 2470-0010A search for (Formula presented) violation in (Formula presented) and (Formula presented) decays is presented using the full Run 1 and Run 2 data samples of (Formula presented) collisions collected with the LHCb detector, corresponding to an integrated luminosity of (Formula presented) at center-of-mass energies of 7, 8, and 13 TeV. For the Run 2 data sample, the (Formula presented)-violating asymmetries are measured to be (Formula presented) and (Formula presented), where the first uncertainty is statistical and the second is systematic. Following significant improvements in the evaluation of systematic uncertainties compared to the previous LHCb measurement, the Run 1 dataset is reanalyzed to update the corresponding results. When combining the Run 2 and updated Run 1 measurements, the final results are found to be (Formula presented) and (Formula presented), constituting the most precise measurements of these asymmetries to date.
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Journal articleAaij R, Abdelmotteleb ASW, Abellan Beteta C, et al., 2025,
Branching fraction measurement of the decay B+ →ψ (2S)φ (1020)K+
, Physical Review D, Vol: 111, ISSN: 2470-0010The branching fraction of the decay B+→ψ(2S)φ(1020)K+, relative to the topologically similar decay B+→J/ψφ(1020)K+, is measured using proton-proton collision data collected by the LHCb experiment at center-of-mass energies of 7, 8, and 13 TeV, corresponding to an integrated luminosity of 9 fb-1. The ratio is found to be 0.061±0.004±0.009, where the first uncertainty is statistical and the second systematic. Using the world-average branching fraction for B+→J/ψφ(1020)K+, the branching fraction for the decay B+→ψ(2S)φ(1020)K+ is found to be (3.0±0.2±0.5±0.2)×10-6, where the first uncertainty is statistical, the second systematic, and the third is due to the branching fraction of the normalization channel.
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Journal articleAalbers J, Abe K, Adrover M, et al., 2025,
Neutrinoless double beta decay sensitivity of the XLZD rare event observatory
, Journal of Physics G Nuclear and Particle Physics, Vol: 52, ISSN: 0954-3899The XLZD collaboration is developing a two-phase xenon time projection chamber with an active mass of 60-80 t capable of probing the remaining weakly interacting massive particle-nucleon interaction parameter space down to the so-called neutrino fog. In this work we show that, based on the performance of currently operating detectors using the same technology and a realistic reduction of radioactivity in detector materials, such an experiment will also be able to competitively search for neutrinoless double beta decay in <sup>136</sup>Xe using a natural-abundance xenon target. XLZD can reach a 3σ discovery potential half-life of 5.7 × 10<sup>27</sup> years (and a 90% CL exclusion of 1.3 × 10<sup>28</sup> years) with 10 years of data taking, corresponding to a Majorana mass range of 7.3-31.3 meV (4.8-20.5 meV). XLZD will thus exclude the inverted neutrino mass ordering parameter space and will start to probe the normal ordering region for most of the nuclear matrix elements commonly considered by the community.
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Journal articleBhattacharya A, Sreeparvathy PC, Ahmed A, et al., 2025,
Giant Topological Hall Effect in Magnetic Weyl Metal Mn2Pd0.5Ir0.5Sn
, Advanced Functional Materials, Vol: 35, ISSN: 1616-301XThe synergy between real and reciprocal space topology is anticipated to yield a diverse array of topological properties in quantum materials. This pursuit is addressed by achieving topologically safeguarded magnetic order in novel Weyl metallic Heusler alloy, Mn<inf>2</inf>Pd<inf>0.5</inf>Ir<inf>0.5</inf>Sn. The system possesses non-centrosymmetric D<inf>2d</inf> crystal symmetry with notable spin-orbit coupling effects. The first principles calculations confirm the topological non-trivial nature of band structure, including 42 pairs of Weyl nodes at/near the Fermi level, offering deeper insights into the observed anomalous Hall effect mediated by intrinsic Berry curvature. A unique canted magnetic ordering facilitates such rich topological features, manifesting through an exceptionally large topological Hall effect at low fields. The latter is sustained even at room temperature and compared with other known topological magnetic materials. Detailed micromagnetic simulations demonstrate the possible existence of an antiskyrmion lattice. These results underscore the D<inf>2d</inf> Heusler magnets as a possible platform to explore the intricate interplay of non-trivial topology across real and reciprocal spaces to leverage a plethora of emergent properties for spintronic applications.
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Journal articleAbratenko P, Alterkait O, Andrade Aldana D, et al., 2025,
First Double-Differential Cross Section Measurement of Neutral-Current π0 Production in Neutrino-Argon Scattering in the MicroBooNE Detector
, Physical Review Letters, Vol: 134, ISSN: 0031-9007We report the first double-differential cross section measurement of neutral-current neutral pion (NCπ0) production in neutrino-argon scattering, as well as single-differential measurements of the same channel in terms of final states with and without protons. The kinematic variables of interest for these measurements are the π0 momentum and the π0 scattering angle with respect to the neutrino beam. A total of 4971 candidate NCπ0 events fully contained within the MicroBooNE detector are selected using data collected at a mean neutrino energy of ∼0.8 GeV from 6.4×1020 protons on target from the Booster Neutrino Beam at the Fermi National Accelerator Laboratory. After extensive data-driven model validation to ensure unbiased unfolding, the Wiener-singular-value-decomposition method is used to extract nominal flux-averaged cross sections. The results are compared to predictions from commonly used neutrino event generators, which tend to overpredict the measured NCπ0 cross section, especially in the 0.2-0.5 GeV/c π0 momentum range and at forward scattering angles. Events with at least one proton present in the final state are also underestimated. This data will help improve the modeling of NCπ0 production, which represents a major background in measurements of charge-parity violation in the neutrino sector and in searches for new physics beyond the standard model.
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Journal articleHayrapetyan A, Tumasyan A, Adam W, et al., 2025,
Measurement of the inclusive cross sections for W and Z boson production in proton-proton collisions at $$ \sqrt{\textrm{s}} $$ = 5.02 and 13 TeV
, Journal of High Energy Physics, Vol: 2025<jats:title>A<jats:sc>bstract</jats:sc> </jats:title> <jats:p>Measurements of fiducial and total inclusive cross sections for W and Z boson production are presented in proton-proton collisions at <jats:inline-formula> <jats:alternatives> <jats:tex-math>$$ \sqrt{s} $$</jats:tex-math> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msqrt> <mml:mi>s</mml:mi> </mml:msqrt> </mml:math> </jats:alternatives> </jats:inline-formula> = 5.02 and 13 TeV. Electron and muon decay modes (<jats:italic>ℓ</jats:italic> = e or <jats:italic>μ</jats:italic>) are studied in the data collected with the CMS detector in 2017, in dedicated runs with reduced instantaneous luminosity. The data sets correspond to integrated luminosities of 298 ± 6 pb<jats:sup> <jats:italic>−</jats:italic>1</jats:sup> at 5.02 TeV and 206 ± 5 pb<jats:sup> <jats:italic>−</jats:italic>1</jats:sup> at 13 TeV. Measured values of the products of the total inclusive cross sections and the branching fractions at 5.02 TeV are <jats:italic>σ</jats:italic>(pp <jats:italic>→</jats:italic> W + X)<jats:inline-formula> <jats:alternatives> <jats:tex-math>$$ \mathcal{B} $$</jats:tex-math> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mi>B</mml:mi> </mml:math> </jats:alternatives> </jats:inline-formula>(W <jats:italic>→ ℓν</jats:italic>) = 7300 <jats:italic>±</jats:italic> 10
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Journal articleHayrapetyan A, Tumasyan A, Adam W, et al., 2025,
Measurement of the inclusive WZ production cross section in pp collisions at $$ \sqrt{\textrm{s}} $$ = 13.6 TeV
, Journal of High Energy Physics, Vol: 2025<jats:title>A<jats:sc>bstract</jats:sc> </jats:title> <jats:p>The inclusive WZ production cross section is measured in proton-proton collisions at a centre-of-mass energy of 13.6 TeV, using data collected during 2022 with the CMS detector, corresponding to an integrated luminosity of 34<jats:italic>.</jats:italic>7 fb<jats:sup> <jats:italic>−</jats:italic>1</jats:sup>. The measurement uses multileptonic final states and a simultaneous likelihood fit to the number of events in four different lepton flavour categories: eee, ee<jats:italic>μ</jats:italic>, <jats:italic>μμ</jats:italic>e, and <jats:italic>μμμ</jats:italic>. The selection is optimized to minimize the number of background events, and relies on an efficient prompt lepton discrimination strategy. The WZ production cross section is measured in a phase space defined within a 30 GeV window around the Z boson mass, as <jats:italic>σ</jats:italic> <jats:sub>total</jats:sub> (pp → WZ) = 55<jats:italic>.</jats:italic>2 ± 1<jats:italic>.</jats:italic>2 (stat) ± 1<jats:italic>.</jats:italic>2 (syst) ± 0<jats:italic>.</jats:italic>8 (lumi) ± 0<jats:italic>.</jats:italic>3 (theo) pb. In addition, the cross section is measured in a fiducial phase space closer to the detector-level requirements. All the measurements presented in this paper are in agreement with standard model predictions.</jats:p>
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Journal articleHayrapetyan A, Tumasyan A, Adam W, et al., 2025,
Search for heavy long-lived charged particles with large ionization energy loss in proton-proton collisions at $$ \sqrt{s} $$ = 13 TeV
, Journal of High Energy Physics, Vol: 2025<jats:title>A<jats:sc>bstract</jats:sc> </jats:title> <jats:p>A search for heavy, long-lived, charged particles with large ionization energy loss within the silicon tracker of the CMS experiment is presented. A data set of proton-proton collisions at a center of mass energy at <jats:inline-formula> <jats:alternatives> <jats:tex-math>$$ \sqrt{s} $$</jats:tex-math> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msqrt> <mml:mi>s</mml:mi> </mml:msqrt> </mml:math> </jats:alternatives> </jats:inline-formula> = 13 TeV, collected in 2017 and 2018 at the CERN LHC, corresponding to an integrated luminosity of 101 fb<jats:sup> <jats:italic>−</jats:italic>1</jats:sup>, is used in this analysis. Two different approaches for the search are taken. A new method exploits the independence of the silicon pixel and strips measurements, while the second method improves on previous techniques using ionization to determine a mass selection. No significant excess of events above the background expectation is observed. The results are interpreted in the context of the pair production of supersymmetric particles, namely gluinos, top squarks, and tau sleptons, and of the Drell-Yan pair production of fourth generation (<jats:italic>τ</jats:italic>′) leptons with an electric charge equal to or twice the absolute value of the electron charge (<jats:italic>e</jats:italic>). An interpretation of a Z’ boson decaying to two <jats:italic>τ</jats:italic>′ leptons with an electric charge equal to 2<jats:italic>e</jats:italic> is presented for the first time. The 95% confidence upper limits on the production cros
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Journal articleHayrapetyan A, Tumasyan A, Adam W, et al., 2025,
Measurement of the inclusive $$ \textrm{t}\overline{\textrm{t}} $$ cross section in final states with at least one lepton and additional jets with 302 pb−1 of pp collisions at $$ \sqrt{\textrm{s}} $$ = 5.02 TeV
, Journal of High Energy Physics, Vol: 2025<jats:title>A<jats:sc>bstract</jats:sc> </jats:title> <jats:p>A measurement of the top quark pair (<jats:inline-formula> <jats:alternatives> <jats:tex-math>$$ \textrm{t}\overline{\textrm{t}} $$</jats:tex-math> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mi>t</mml:mi> <mml:mover> <mml:mi>t</mml:mi> <mml:mo>¯</mml:mo> </mml:mover> </mml:math> </jats:alternatives> </jats:inline-formula>) production cross section in proton-proton collisions at a centre-of-mass energy of 5.02 TeV is presented. The data were collected at the LHC in autumn 2017, in dedicated runs with low-energy and low-intensity conditions with respect to the default configuration, and correspond to an integrated luminosity of 302 pb<jats:sup> <jats:italic>−</jats:italic>1</jats:sup>. The measurement is performed using events with one electron or muon, and multiple jets, at least one of them being identified as originating from a b quark (b tagged). Events are classified based on the number of all reconstructed jets and of b-tagged jets. Multivariate analysis techniques are used to enhance the separation between the signal and backgrounds. The measured cross section is <jats:inline-formula> <jats:alternatives> <jats:tex-math>$$ 62.5\pm 1.6{\left(\textrm{stat}\right)}_{-2.5}^{+2.6}\left(\textrm{syst}\right)\pm 1.2\left(\textrm{lumi}\right) $$</jats:tex-math> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mn>62.5</mml:mn> <mml:mo>±</mml:mo> <
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