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Journal articleMorgan K, Azuma T, Baptista G, et al., 2026,
Transition-Edge Sensor Spectrometer for Precision Spectroscopy of Antiprotonic Atoms
, IEEE Transactions on Applied Superconductivity, Vol: 36, ISSN: 1051-8223antiProtonic Atom X-ray (PAX) spectroscopy is an experiment that aims to test strong-field quantum electrodynamics (QED) effects by performing high-precision X-ray spectroscopy of antiprotonic atoms. PAX will use a low-energy antiproton beam provided by the Extra Low ENergy Antiproton (ELENA) ring at the European Organization for Nuclear Research (CERN) to create antiprotonic atoms. A superconducting transition-edge sensor (TES) spectrometer will be used to measure the energy of transitions between circular Rydberg states in these atoms. The energy range of interest for the experiment spans 50 keV to 250 keV, and the desired precision for measuring the centroids of the emission lines is 10^{-5}. The spectrometer for PAX is intended to have four 96-pixel TES arrays and will be read out with a microwave superconducting quantum interference device (SQUID) multiplexer. As a step toward building the full instrument, we built a scaled-down version of the spectrometer that was installed at the TEst Line for Machine And Antimatter eXperiments (TELMAX) facility at ELENA in April 2025. The purpose of this deployment was to make an observation of X-ray emission by antiprotonic atoms and to better understand the effect of the pionic charged particle background due to antiproton annihilation on the performance of the TES array. This pilot spectrometer had an array of 60 TES pixels in a compact adiabatic demagnetization refrigerator cryostat. The sensors were read out with a microwave SQUID multiplexer. Each pixel consisted of a molybdenum/gold bilayer TES with a coplanar gold “landing pad” for a bulk tin absorber that was attached by an epoxy joint. We discuss the design of the TES pixels, the microwave SQUID readout, and the cryogenic platform. Finally, we present calibration data obtained at TELMAX using radioactive sources to assess the performance of the spectrometer in the antiproton beam-off condition.
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Journal articleWalker T, Marchant AL, Bentine E, et al., 2026,
A high-flux source of cold strontium with a loading rate of 4×1010 atoms/s for open release
, Avs Quantum Science, Vol: 8We present a high-flux source of cold strontium atoms based on a two-dimensional magneto-optical trap (2D MOT) and a Zeeman slower. We use the source to load a 3D MOT in a separate science chamber, observing a loading rate of 4 × 10<sup>10</sup> atoms / s—to our knowledge, the highest reported loading flux for strontium. To characterize the vacuum pressure in the science chamber, we load the atoms into a magnetic trap and measure a lifetime of between 8 and 24 s, depending on the oven temperature. Finally, we characterize the atom flux and velocity distributions from the oven and from the 2D MOT source, finding reasonable agreement with models in the free molecular flow regime. Our results show that it is possible to readily produce a cold strontium flux at comparable levels to those of alkali species, at oven temperatures compatible with long-term operation, and at vacuum pressures suitable for state-of-the-art quantum experiments. We make our design available at no cost to benefit researchers in the quantum community.
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Journal articleBelyaev A, Gevorgyan A, Hayrapetyan A, et al., 2026,
System-size dependence of charged-particle suppression in ultrarelativistic nucleus-nucleus collisions
, Physics Letters B, Vol: 880, Pages: 140679-140679, ISSN: 0370-2693 -
Journal article, 2026,
Machine-learning techniques for model-independent searches in dijet final states
, Machine Learning: Science and Technology, Vol: 7, Pages: 045008-045008<jats:title>Abstract</jats:title> <jats:p> Anomaly detection methods used in a recent search for new phenomena by CMS at the CERN LHC are presented. The methods use machine learning to detect anomalous jets produced in the decay of new massive particles without depending on a specific theory model. The effectiveness of these approaches in enhancing sensitivity to various simulated signal samples is studied and compared using data collected in proton–proton collisions at a center-of-mass energy of 13 <jats:inline-formula> <jats:tex-math> </jats:tex-math> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mrow> <mml:mrow> <mml:mstyle scriptlevel="0"/> <mml:mtext>TeV</mml:mtext> </mml:mrow> </mml:mrow> </mml:math> </jats:inline-formula> . In an example analysis, the capabilities of anomaly detection methods are further demonstrated by identifying large-radius jets consistent with Lorentz-boosted hadronically decaying top quarks in a model-agnostic framework. </jats:p>
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Journal articleHayrapetyan A, Makarenko V, Tumasyan A, et al., 2026,
Search for soft unclustered energy patterns produced in association with a W or Z boson in proton-proton collisions at s=13TeV
, Physics Letters Section B Nuclear Elementary Particle and High Energy Physics, Vol: 879, ISSN: 0370-2693A search for a Higgs boson produced in association with a W or Z boson and decaying via a soft unclustered energy pattern (SUEP) is presented. The analysis is based on proton-proton collision data corresponding to an integrated luminosity of 138fb<sup>−1</sup> collected between 2016 and 2018 at the LHC. Final states with a leptonic W or Z boson decay associated with a high multiplicity of low-momentum charged particles are explored for the first time. The results show no significant excess over the standard model background expectation. Limits are set on the production cross section of a Higgs boson that decays to a SUEP, for a range of parameters of the SUEP model. Material is provided to facilitate further interpretation of the results.
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Journal articleWaiton J, Bateman J, Evans JJ, et al., 2026,
A sterile-neutrino search using data from the MicroBooNE liquid-argon time projection chamber performed in an undergraduate teaching laboratory
, European Journal of Physics, Vol: 47, Pages: 045203-045203, ISSN: 0143-0807<jats:title>Abstract</jats:title> <jats:p>Fundamental particle physics is a key part of an undergraduate physics curriculum, but can be challenging to incorporate into teaching laboratories. We present an undergraduate laboratory experiment that enables students to work with real data from the MicroBooNE liquid-argon time projection chamber to search for the existence of a sterile neutrino: a new, fourth, neutrino state. This search has galvanised physicists for decades, as the existence of sterile neutrinos could play a critical role in understanding fundamental processes in the early Universe, provide viable dark matter candidates, and offer a natural explanation for the origin of neutrino masses. From an experimental point of view, anomalies observed in several neutrino experiments provide tantalising hints of their existence. The analysis presented here, whilst based on real data, has been adapted as a pedagogical tool for an undergraduate teaching laboratory, in which students are asked to develop an understanding of neutrino oscillation theory, analyse a MicroBooNE data sample, and apply statistical methods to search for a potential sterile neutrino. The analysis incorporates machine learning techniques to improve event classification. Students are encouraged to explore these and other methods to optimise their results.</jats:p>
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Journal articleHayrapetyan A, Makarenko V, Tumasyan A, et al., 2026,
Search for a boosted Higgs boson decaying to bottom quark pairs in association with a W or Z boson in proton-proton collisions at s=13TeV
, Physics Letters B, Vol: 879, Pages: 140534-140534, ISSN: 0370-2693 -
Journal articleHayrapetyan A, Makarenko V, Tumasyan A, et al., 2026,
Measurement of the Υ(1S), Υ(2S), and Υ(3S) differential cross sections in pp collisions at $$ \sqrt{s}=13.6 $$ TeV
, Journal of High Energy Physics, Vol: 2026<jats:title> A <jats:sc>bstract</jats:sc> </jats:title> <jats:p> The production cross sections of the Υ(1S), Υ(2S), and Υ(3S) mesons are measured in proton-proton collisions at <jats:inline-formula> <jats:alternatives> <jats:tex-math>$$ \sqrt{s}=13.6 $$</jats:tex-math> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msqrt> <mml:mi>s</mml:mi> </mml:msqrt> <mml:mo>=</mml:mo> <mml:mn>13.6</mml:mn> </mml:math> </jats:alternatives> </jats:inline-formula> TeV, using a data sample collected in 2022 by the CMS experiment and corresponding to an integrated luminosity of 37.4 fb <jats:sup> <jats:italic>−</jats:italic> 1 </jats:sup> . The measurement is performed in the μ <jats:sup>+</jats:sup> μ <jats:sup> <jats:italic>−</jats:italic> </jats:sup> decay channels, differentially as a function of transverse momentum in the 20–200 GeV range, in the | <jats:italic>y</jats:italic> | <jats:italic><</jats:italic> 0 <jats:italic>.</jats:italic> 6 and 0 <jats:italic&
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Journal articleHayrapetyan A, Makarenko V, Tumasyan A, et al., 2026,
Search for the pair production of long-lived supersymmetric partners of the tau lepton in proton-proton collisions at $$ \sqrt{s}=13 $$ TeV
, Journal of High Energy Physics, Vol: 2026<jats:title> A <jats:sc>bstract</jats:sc> </jats:title> <jats:p> Gauge-mediated supersymmetry-breaking models provide a strong motivation to search for a supersymmetric partner of the tau lepton (stau) with a macroscopic lifetime. Long-lived stau decays produce tau leptons that are displaced from the primary proton-proton interaction vertex, leading to an unconventional signature. This paper presents a search for the direct production of long-lived staus decaying within the CMS tracker volume in proton-proton collisions at <jats:inline-formula> <jats:alternatives> <jats:tex-math>$$ \sqrt{s}=13 $$</jats:tex-math> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msqrt> <mml:mi>s</mml:mi> </mml:msqrt> <mml:mo>=</mml:mo> <mml:mn>13</mml:mn> </mml:math> </jats:alternatives> </jats:inline-formula> TeV, performed for the first time with an identification algorithm based on a graph neural network dedicated to displaced tau leptons. The data sample, corresponding to an integrated luminosity of 138 fb <jats:sup> <jats:italic>−</jats:italic> 1 </jats:sup> , was recorded with the CMS experiment at the CERN LHC between 2016 and 2018. This search excludes, at 95% confidence level, stau masses, <jats:inline-formula> <jats:alternatives> <jats:tex-math&g
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Journal articleAaij R, Abdelfatah M, Abdelmotteleb ASW, et al., 2026,
Observation of the Doubly Charmed Baryon Ξ_{cc}^{+} with the LHCb Run 3 Detector.
, Phys Rev Lett, Vol: 137The first observation of the doubly charmed baryon Ξ_{cc}^{+} is reported through its decay to the Λ_{c}^{+}K^{-}π^{+} final state, with a statistical significance exceeding seven standard deviations. The observation is made using proton-proton collision data collected in 2024 with the LHCb Run 3 detector at a center-of-mass energy of 13.6 TeV, corresponding to a total integrated luminosity of 6.9 fb^{-1}. The Ξ_{cc}^{+} mass is measured to be 3619.97±0.83±0.26_{-1.30}^{+1.90} MeV/c^{2}, where the first uncertainty is statistical, the second is systematic, and the third is due to the unknown Ξ_{cc}^{+} lifetime, which is assumed to lie in the range 15-160 fs with a baseline value of 45 fs. The difference between the masses of the Ξ_{cc}^{+} and Ξ_{cc}^{++} baryons is determined to be -1.77±0.84±0.15_{-1.30}^{+1.90} MeV/c^{2}. This is the first observation of a new particle made with the LHCb Run 3 detector.
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Journal articleAaij R, Abdelmotteleb ASW, Abellan Beteta C, et al., 2026,
Comprehensive Analysis of the B^{0}→K^{*0}μ^{+}μ^{-} Decay.
, Phys Rev Lett, Vol: 137An analysis of the B^{0}→K^{*0}(→K^{+}π^{-})μ^{+}μ^{-} decay is presented using proton-proton collision data collected by the LHCb experiment, corresponding to an integrated luminosity of 8.4 fb^{-1}. The full set of CP-averaged and CP-asymmetric angular observables is determined in bins of the invariant mass squared of the dimuon system, as well as the branching fraction relative to the B^{0}→J/ψ(→μ^{+}μ^{-})K^{+}π^{-} decay. For the first time, the full set of observables pertaining to the K^{+}π^{-} S-wave contribution to the final state are presented and consideration is given to effects arising from the mass of the muons. The extracted CP-asymmetry observables show no significant deviations from zero. The measurements of the CP-averaged observables and the branching fractions continue to exhibit the pattern of tensions with the standard model predictions that have been seen in previous analyses that use part of the dataset considered in this Letter.
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Journal articleHayrapetyan A, Makarenko V, Tumasyan A, et al., 2026,
Measurement of <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"> <mml:mi>B</mml:mi> </mml:math> meson production fraction ratios in proton-proton collisions at <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"> <mml:mrow> <mml:msqrt> <mml:mrow> <mml:mi>s</mml:mi> </mml:mrow> </mml:msqrt> <mml:mo>=</mml:mo> <mml:mn>13</mml:mn> <mml:mtext> </mml:mtext> <mml:mtext> </mml:mtext> <mml:mi>TeV</mml:mi> </mml:mrow> </mml:math> using open-charm and charmonium decays
, Physical Review D, Vol: 114, ISSN: 2470-0010<jats:p> Production fraction ratios of <a:math xmlns:a="http://www.w3.org/1998/Math/MathML" display="inline"> <a:msup> <a:mi>B</a:mi> <a:mo>+</a:mo> </a:msup> </a:math> , <c:math xmlns:c="http://www.w3.org/1998/Math/MathML" display="inline"> <c:msup> <c:mi>B</c:mi> <c:mn>0</c:mn> </c:msup> </c:math> , and <e:math xmlns:e="http://www.w3.org/1998/Math/MathML" display="inline"> <e:msubsup> <e:mi>B</e:mi> <e:mi>s</e:mi> <e:mn>0</e:mn> </e:msubsup> </e:math> mesons are measured in proton-proton collisions at <g:math xmlns:g="http://www.w3.org/1998/Math/MathML" display="inline"> <g:mrow> <g:msqrt> <g:mrow> <g:mi>s</g:mi> </g:mrow> </g:msqrt> <g:mo>=</g:mo> <g:mn>13</g:mn> <g:mtext> </g:mtext> <g:mtext> </g:mtext> <g:mi>TeV</g:mi> </g:mrow> </g:math> using a special dataset recorded in 2018 with high-rate
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Journal articleHayrapetyan A, Makarenko V, Tumasyan A, et al., 2026,
Search for heavy long-lived charged particles with level-1 trigger scouting data from proton-proton collisions at s=13.6TeV
, Physics Letters Section B Nuclear Elementary Particle and High Energy Physics, Vol: 878, ISSN: 0370-2693A search for heavy long-lived charged particles at the LHC is presented. Particles traversing the CMS muon detector across several bunch crossings are searched for using a data sample of proton-proton collisions at s=13.6TeV collected with the CMS detector in 2024, corresponding to an integrated luminosity of 3.7 fb<sup>−1</sup>. This is the first search using the novel level-1 trigger scouting data set collected without any trigger selection, allowing correlations between bunch crossings to be analyzed. The results are interpreted as upper limits on the cross sections of several benchmark processes with pair production of heavy long-lived charged particles. Upper limits on the fiducial cross section of a heavy long-lived charged particle with p<inf>T</inf>>500GeV and | η | < 0.83 are also set in different ranges of β=v/c. This analysis is a proof of concept for the level-1 trigger data scouting system and complements existing searches for heavy long-lived charged particles by extending the sensitivity to lower β values.
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Journal articleHayrapetyan A, Makarenko V, Tumasyan A, et al., 2026,
Combination of searches for heavy vector boson resonances in proton-proton collisions at s=13 TeV
, Journal of High Energy Physics, Vol: 2026A combined statistical analysis of searches for heavy vector boson resonances decaying into pairs of W, Z, or Higgs bosons, as well as into quark pairs qq¯bb¯tt¯tb¯ or lepton pairs ℓ+ℓ−ℓν¯, with ℓ = e, μ, τ, is presented. The results are based on proton-proton collision data at a center-of-mass energy of 13 TeV, corresponding to an integrated luminosity of 138 fb<sup>−1</sup>, collected by the CMS experiment from 2016 to 2018. No significant deviation from the expectations of the standard model is observed. The results are interpreted in the simplified heavy vector triplet (HVT) framework, setting 95% confidence level upper limits on the production cross sections and on the coupling strengths of the HVT bosons to standard model particles. The results exclude HVT resonances with masses below 5.5 TeV in a weakly coupled scenario, below 4.8 TeV in a strongly coupled scenario, and up to 2.0 TeV in the case of production via vector boson fusion. The combination provides the most stringent constraints to date on new phenomena predicted by the HVT model.
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Journal articleChekhovsky V, Hayrapetyan A, Makarenko V, et al., 2026,
Search for a new neutral gauge boson produced in association with one or two b jets and decaying into a pair of muons in proton-proton collisions at s=13 TeV
, Journal of High Energy Physics, Vol: 2026A search for a new neutral gauge boson, Z′, produced in association with one or two jets, including at least one b jet, and decaying into a pair of muons is presented. The analysis uses proton-proton collision data collected with the CMS detector at s=13 TeV, corresponding to an integrated luminosity of 138 fb<sup>−1</sup>. No significant deviation from background expectations is observed. Upper limits at 95% confidence level on the product of cross section, branching fraction to dimuons, acceptance, and efficiency, from 0.2 to 2 fb, are set for Z′ boson masses between 125 and 350 GeV. Process-dependent products of acceptance and efficiency, and model-independent limits on the signal yield are provided. These are the only results to date in the 125–200 GeV mass range and the most stringent for b quark fusion production modes in the 200–350 GeV range, complementing inclusive Z′ boson searches.
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Journal articleAad G, Aakvaag E, Abbott B, et al., 2026,
Search for long-lived particles using displaced vertices of oppositely charged leptons in 140fb−1 of pp collisions at s=13 TeV with the ATLAS detector
, Physics Letters Section B Nuclear Elementary Particle and High Energy Physics, Vol: 878, ISSN: 0370-2693A search is presented for long-lived particles decaying into an oppositely charged lepton pair, μ<sup>+</sup>μ<sup>−</sup>, e<sup>+</sup>e<sup>−</sup>, or e <sup> ± </sup> μ <sup>∓</sup>, that form a vertex within the inner tracking system of the ATLAS detector at the Large Hadron Collider, displaced from the primary proton–proton interaction region. The analysis uses the 140 fb<sup>−1</sup> of Run-2 data collected at s=13 TeV by the ATLAS experiment in 2015–2018. The results of the analysis are interpreted in the context of three benchmark models covering masses from 0.1 to 2.2 TeV and a range of mean proper lifetimes times the speed of light from 1 to 10 000 mm. The first model is a generic Z ′ boson pair-produced by a new heavy scalar, with the Z ′ decaying into lepton pairs. The remaining two models are R -parity violating supersymmetric models in which the lightest neutralino χ˜<inf>1</inf><sup>0</sup> decays into ℓ<sup>+</sup>ℓ<sup><sup>′</sup><sup>−</sup></sup>ν (ℓ,ℓ<sup>′</sup>=e, μ). The models differ by the mode of production of the χ˜<inf>1</inf><sup>0</sup>, which can be produced via the decay of pairs of gluinos or of pairs of charginos and neutralinos (χ˜<inf>1</inf><sup>±</sup>χ˜<inf>1</inf><sup>0</sup>, χ˜<inf>1</inf><sup>±</sup>χ˜<inf>2</inf><sup>0</sup>, or χ˜<inf>2</inf><sup>0</sup>χ˜<inf>1</inf><sup>0</sup>). Although each benchmark sample includes pair-produced LLPs, only a single vertex is required to be reconstructed. No dilepton displaced v
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Journal articleHayrapetyan A, Makarenko V, Tumasyan A, et al., 2026,
Measurement of the jet mass in hadronic decays of boosted W bosons at 13 TeV and extraction of the W boson mass
, Journal of High Energy Physics, Vol: 2026The jet mass of W bosons decaying to a quark-antiquark pair is measured in W+jets events from proton-proton collisions at a center-of-mass energy of 13 TeV. The data used were collected by the CMS experiment at the CERN LHC and correspond to an integrated luminosity of 138 fb<sup>−1</sup>. Hadronic decays of W bosons with high momenta produce strongly collimated decay products due to the large Lorentz boost, and are reconstructed as single large-radius jets. These jets have a characteristic substructure that is exploited to distinguish them from the large background of quark- and gluon-initiated jets. The jet mass is computed using the soft-drop algorithm, which suppresses soft wide-angle radiation that leads to a broadening of the jet mass distribution. For the first time, unfolded measurements are presented of the double-differential W+jets cross section as a function of the jet transverse momentum and soft-drop mass. From these distributions, the W boson mass is obtained, with a value of 80.83 ± 0.55 GeV in a scheme with mass-dependent width, achieving the smallest uncertainty available today from an all-jets final state at a hadron collider.
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Journal articleAbe K, Abe S, Asaoka Y, et al., 2026,
Search for Diffuse Supernova Neutrino Background with 956.2 Days of Super-Kamiokande Gadolinium Dataset
, Astrophysical Journal, Vol: 1005, ISSN: 0004-637XWe report the search result for the Diffuse Supernova Neutrino Background (DSNB) in neutrino energies beyond 9.3 MeV in the gadolinium-loaded Super-Kamiokande (SK) detector with a 22,500 × 956.2 m<sup>3</sup> day exposure. Starting in the summer of 2020, SK introduced 0.01% gadolinium (Gd) by mass into its ultrapure water to enhance the neutron capture signal, termed the SK-VI phase. This was followed by a 0.03% Gd-loading in 2022, a phase referred to as SK-VII. We then conducted a DSNB search using 552.2 days of SK-VI data and 404.0 days of SK-VII data through 2023 September. This analysis includes several new features, such as two new machine learning neutron detection algorithms with Gd, an improved atmospheric background-reduction technique, and two parallel statistical approaches. No significant excess over background predictions was found in a DSNB spectrum-independent analysis, and 90% confidence level (C.L.) upper limits on the astrophysical electron antineutrino flux were set. Additionally, a spectral fitting result exhibited a ∼1.2σ disagreement with a null DSNB hypothesis, comparable to a previous result from 5823 days of all SK pure-water phases.
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Journal articleHayrapetyan A, Makarenko V, Tumasyan A, et al., 2026,
Search for single production of a vector-like T quark decaying to a top quark and a neutral scalar boson in the lepton+jets final state in proton-proton collisions at s=13 TeV
, Journal of High Energy Physics, Vol: 2026A search for single production of a vector-like T quark with charge 2e/3, decaying to a top quark and a neutral scalar boson is presented. The boson can be a standard model Higgs boson (H) or a new scalar boson (ϕ). In the first case, a branching fraction of 25% is assumed for the decay T → tH, while in the second case the T quark is assumed to decay exclusively to tϕ. The top quark is identified via its lepton+jets decay, and the neutral boson via its decay into a bottom quark-antiquark pair. Final states with Lorentz-boosted topologies are considered and machine-learning techniques are exploited for optimal event classification. The analysis uses data collected by the CMS experiment in proton-proton collisions at a center-of-mass energy of 13 TeV, corresponding to an integrated luminosity of 138 fb<sup>−1</sup> recorded at the CERN LHC in 2016–2018. Upper limits at 95% confidence level are set on the product of cross section and branching fraction for a T quark in a narrow-width approximation. They vary between 14.7 and 0.1 fb, for T quark masses in the range 1.3–3.0 TeV and ϕ boson masses in the range 25–250 GeV. These are the first exclusion limits set on the production of a single T quark decaying into a top quark and a new neutral scalar boson. For the decay channel into a top quark and a standard model Higgs boson, the results provide the best limits on production cross sections to date, for T quark masses above 2 TeV.
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Journal articleAprile E, Aalbers J, Abe K, et al., 2026,
Low-energy nuclear recoil calibration of XENONnT with a <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"> <mml:mrow> <mml:mrow> <mml:mmultiscripts> <mml:mrow> <mml:mi mathvariant="normal">Y</mml:mi> </mml:mrow> <mml:mprescripts/> <mml:none/> <mml:mrow> <mml:mn>88</mml:mn> </mml:mrow> </mml:mmultiscripts> </mml:mrow> <mml:mi>Be</mml:mi> </mml:mrow> </mml:math> photoneutron source
, Physical Review D, Vol: 113, ISSN: 2470-0010<jats:p> Characterizing low-energy, keV-range nuclear recoils near the detector threshold is one of the major challenges for large direct dark matter detectors. To that end, we have successfully used an Yttrium-Beryllium photoneutron source that emits 152 keV neutrons for the calibration of the light and charge yields of the XENONnT experiment for the first time. After data selection, we accumulated 474 events from 183 hours of exposure with this source. The expected background was <a:math xmlns:a="http://www.w3.org/1998/Math/MathML" display="inline"> <a:mn>55</a:mn> <a:mo>±</a:mo> <a:mn>12</a:mn> </a:math> accidental coincidence events, estimated using a dedicated 152 hour background calibration run with a Yttrium-PVC gamma-only source and data-driven modeling. From these calibrations, we extracted the light (charge) yield for liquid xenon at our field strength of <c:math xmlns:c="http://www.w3.org/1998/Math/MathML" display="inline"> <c:mrow> <c:mn>23</c:mn> <c:mtext> </c:mtext> <c:mtext> </c:mtext> <c:mi mathvariant="normal">V</c:mi> <c:mo>/</c:mo> <c:mi>cm</c:mi> </c:mrow> </c:math> between 0.3 (0.7) <f:math xmlns:f="http://www.w3.org/1998/Math/MathML" display="inline"> <f:msub> <f:mi>keV</f:mi> <f:mi>NR</f:mi>
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Journal articleAnonymous, 2026,
Measurements of the electron neutrino-argon differential cross section without pions in the final state in MicroBooNE
, Physical Review D, ISSN: 2470-0010 -
Journal articleAaij R, Abdelmotteleb ASW, Abellan Beteta C, et al., 2026,
First Measurement of Time-Dependent CP Violation in the Flavor-Changing Neutral-Current Decay B^{0}→K_{S}^{0}μ^{+}μ^{-}.
, Phys Rev Lett, Vol: 136A flavor-tagged time-dependent analysis of B^{0}→K_{S}^{0}μ^{+}μ^{-} decays is performed across the full dimuon mass range excluding the J/ψ and ψ(2S) resonance regions. The analysis uses proton-proton collision data collected by the LHCb experiment in 2011-2018 at center-of-mass energies of 7, 8, and 13 TeV, corresponding to an integrated luminosity of 9 fb^{-1}. The CP violation parameters are determined to be C=-0.13±0.32±0.04, S=+0.82±0.29±0.05, where the first uncertainties are statistical and the second are systematic. The results are consistent with the standard model prediction. This is the first experimental study of time-dependent CP violation in b→sℓ^{+}ℓ^{-} processes.
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Journal articleHayrapetyan A, Makarenko V, Tumasyan A, et al., 2026,
Search for pair production of heavy resonances in final states with a photon and large-radius jets in proton-proton collisions at <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"> <mml:mrow> <mml:msqrt> <mml:mrow> <mml:mi>s</mml:mi> </mml:mrow> </mml:msqrt> <mml:mo>=</mml:mo> <mml:mn>13</mml:mn> <mml:mtext> </mml:mtext> <mml:mtext> </mml:mtext> <mml:mi>TeV</mml:mi> </mml:mrow> </mml:math>
, Physical Review D, Vol: 113, ISSN: 2470-0010<jats:p> A search for the pair production of heavy spin- <a:math xmlns:a="http://www.w3.org/1998/Math/MathML" display="inline"> <a:mn>1</a:mn> <a:mo>/</a:mo> <a:mn>2</a:mn> </a:math> or spin- <c:math xmlns:c="http://www.w3.org/1998/Math/MathML" display="inline"> <c:mn>3</c:mn> <c:mo>/</c:mo> <c:mn>2</c:mn> </c:math> resonances ( <e:math xmlns:e="http://www.w3.org/1998/Math/MathML" display="inline"> <e:msup> <e:mi>t</e:mi> <e:mo>*</e:mo> </e:msup> </e:math> ) in proton-proton collisions at <g:math xmlns:g="http://www.w3.org/1998/Math/MathML" display="inline"> <g:msqrt> <g:mi>s</g:mi> </g:msqrt> <g:mo>=</g:mo> <g:mn>13</g:mn> <g:mtext> </g:mtext> <g:mtext> </g:mtext> <g:mi>TeV</g:mi> </g:math> is presented. Data collected with the CMS detector at the CERN LHC from 2016 to 2018 corresponding to an integrated luminosity of <i:math xmlns:i="http://www.w3.org/1998/Math/MathML" display="inline"> <i:mn>138</i:mn> <i:mtext
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Journal articleAaij R, Abdelmotteleb ASW, Abellan Beteta C, et al., 2026,
Measurement of the Top-Quark Production Cross Section and Charge Asymmetry at LHCb.
, Phys Rev Lett, Vol: 136The first measurements of the top- and antitop-quark differential production cross sections and the top-quark charge asymmetry in the forward region are presented, using proton-proton collision data collected by the LHCb experiment at a center-of-mass energy of 13 TeV corresponding to an integrated luminosity of 5.4 fb^{-1}. The total production cross sections of top and antitop quarks are also determined. Measurements are performed using the μ+b-jet final state within a fiducial region defined by b-jet p_{T,jet}>50 GeV and pseudorapidity 2.2<η_{jet}<4.0, with the muon from the W-boson decay required to have p_{T,μ}>25 GeV and 2.0<η_{μ}<4.5. The muon and b-jet system must satisfy p_{T}(μ+jet)>20 GeV. The measured integrated production cross sections for the top and antitop quarks are σ_{t}=0.95±0.04±0.08±0.02 pb, σ_{t[over ¯]}=0.81±0.03±0.07±0.02 pb, where the first uncertainty is statistical, the second systematic, and the third accounts for the luminosity uncertainty. The top-quark charge asymmetry is measured to be A_{C}^{t}=0.08±0.03±0.01, where the first uncertainty is statistical and the second is systematic. These results are consistent with next-to-leading order Standard Model predictions.
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Journal articleChekhovsky V, Hayrapetyan A, Makarenko V, et al., 2026,
Measurement of the ratio of the <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"> <mml:msubsup> <mml:mi>B</mml:mi> <mml:mi>c</mml:mi> <mml:mo>+</mml:mo> </mml:msubsup> <mml:mo stretchy="false">→</mml:mo> <mml:mi>J</mml:mi> <mml:mo>/</mml:mo> <mml:mi>ψ</mml:mi> <mml:msup> <mml:mi>τ</mml:mi> <mml:mo>+</mml:mo> </mml:msup> <mml:msub> <mml:mi>ν</mml:mi> <mml:mi>τ</mml:mi> </mml:msub> </mml:math> and <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"> <mml:msubsup> <mml:mi>B</mml:mi> <mml:mi>c</mml:mi> <mml:mo>+</mml:mo> </mml:msubsup> <mml:mo stretchy="false">→</mml:mo> <mml:mi>J</mml:mi> <mml:mo>/</mml:mo> <mml:mi>ψ</mml:mi> <mml:msup> <mml:mi>μ</mml:mi> <mml:mo>+</mml:mo> </mml:msup> <mml:msub> <mml:mi>ν</mml:mi> <mml:mi>μ</mml:mi> </mml:msub> </mml:math> branching fractions using three-prong <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"> <mml:mi>τ</mml:mi> </mml:math> lepton decays
, Physical Review D, Vol: 113, ISSN: 2470-0010<jats:p> The ratio between the <a:math xmlns:a="http://www.w3.org/1998/Math/MathML" display="inline"> <a:mrow> <a:msubsup> <a:mi>B</a:mi> <a:mi>c</a:mi> <a:mo>+</a:mo> </a:msubsup> <a:mo stretchy="false">→</a:mo> <a:mrow> <a:mi>J</a:mi> <a:mo>/</a:mo> <a:mi>ψ</a:mi> </a:mrow> </a:mrow> <a:msup> <a:mi>τ</a:mi> <a:mo>+</a:mo> </a:msup> <a:msub> <a:mi>ν</a:mi> <a:mi>τ</a:mi> </a:msub> </a:math> and <d:math xmlns:d="http://www.w3.org/1998/Math/MathML" display="inline"> <d:mrow> <d:msubsup> <d:mi>B</d:mi> <d:mi>c</d:mi> <d:mo>+</d:mo> </d:msubsup> <d:mo stretchy="false">→</d:mo> <d:mrow> <d:mi>J</d:mi> <d:mo>/</d:mo> <d:mi>ψ</d:mi> </d:mrow> </d:mrow> <d:msup>
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Journal articleAbbaslu S, Abed Abud A, Acciarri R, et al., 2026,
Measurement of exclusive <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"> <mml:mrow> <mml:msup> <mml:mrow> <mml:mi>π</mml:mi> </mml:mrow> <mml:mrow> <mml:mo>+</mml:mo> </mml:mrow> </mml:msup> </mml:mrow> </mml:math> -argon interactions using ProtoDUNE-SP
, Physical Review D, Vol: 113, ISSN: 2470-0010<jats:p> We present the measurement of <a:math xmlns:a="http://www.w3.org/1998/Math/MathML" display="inline"> <a:msup> <a:mi>π</a:mi> <a:mo>+</a:mo> </a:msup> </a:math> -argon inelastic cross sections using the ProtoDUNE single-phase liquid argon time projection chamber in the incident <c:math xmlns:c="http://www.w3.org/1998/Math/MathML" display="inline"> <c:msup> <c:mi>π</c:mi> <c:mo>+</c:mo> </c:msup> </c:math> kinetic energy range of 500–800 MeV in multiple exclusive channels (absorption, charge exchange, and the remaining inelastic interactions). The results of this analysis are important inputs to simulations of liquid argon neutrino experiments such as the Deep Underground Neutrino Experiment and the Short Baseline Neutrino program at Fermi National Accelerator Laboratory. They will be employed to improve the modeling of final state interactions within neutrino event generators used by these experiments, as well as the modeling of <e:math xmlns:e="http://www.w3.org/1998/Math/MathML" display="inline"> <e:msup> <e:mi>π</e:mi> <e:mo>+</e:mo> </e:msup> </e:math> -argon secondary interactions within the liquid argon. This is the first measurement of <g:math xmlns:g="http://www.w3.org/1998/Math/MathML" display="inline"> <g:msup
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Journal articleAaij R, Abdelmotteleb ASW, Abellan Beteta C, et al., 2026,
Erratum to: Measurement of CP asymmetry in D0 → K0SK0S decays with Run 3 data (Journal of High Energy Physics, (2026), 2026, 2, (253), 10.1007/JHEP02(2026)253)
, Journal of High Energy Physics, Vol: 2026Due to a typesetting error, the title of the published version was wrong. The correct title is “Measurement of CP asymmetry in D<sup>0</sup> → K<sup>0</sup> <inf>S</inf>K<sup>0</sup> <inf>S</inf> decays with the LHCb Run 3 detector” The originally published wrong file has been replaced online.
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Journal articleYankelevich A, Abe K, Asaoka Y, et al., 2026,
Measurement of the solar neutrino interaction rate below 3.49 MeV in Super-Kamiokande-IV
, Physical Review D, Vol: 113, ISSN: 2470-0010<jats:p> Super-Kamiokande (SK) has observed <a:math xmlns:a="http://www.w3.org/1998/Math/MathML" display="inline"> <a:mrow> <a:mmultiscripts> <a:mrow> <a:mi mathvariant="normal">B</a:mi> </a:mrow> <a:mprescripts/> <a:none/> <a:mrow> <a:mn>8</a:mn> </a:mrow> </a:mmultiscripts> </a:mrow> </a:math> solar neutrino elastic scattering at recoil electron kinetic energies ( <d:math xmlns:d="http://www.w3.org/1998/Math/MathML" display="inline"> <d:msub> <d:mi>E</d:mi> <d:mi>kin</d:mi> </d:msub> </d:math> ) as low as 3.49 MeV to study neutrino flavor conversion within the Sun. At SK-observable energies, these conversions are dominated by the Mikheyev-Smirnov-Wolfenstein effect. An upturn in the electron neutrino survival probability in which vacuum neutrino oscillations become dominant is predicted to occur at lower energies, but radioactive background increases exponentially with decreasing energy. New machine learning approaches provide substantial background reduction below 3.49 MeV such that statistical extraction of solar neutrino interactions becomes feasible. This article presents an analysis of the solar neutrino interaction rate at <f:math xmlns:f="http://www.w3.org/1998/Math/MathML" display="inline">
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Journal articleAad G, Aakvaag E, Abbott B, et al., 2026,
Search for Higgs bosons produced in association with a high-energy photon via vector-boson fusion and decaying to a pair of b-quarks in the ATLAS detector
, Physics Letters Section B Nuclear Elementary Particle and High Energy Physics, Vol: 877, ISSN: 0370-2693A search for Standard Model Higgs bosons produced in association with a high-energy photon and decaying to bb¯ is performed using 133 fb<sup>−1</sup> of s=13 TeV pp collision data collected with the ATLAS detector at the Large Hadron Collider at CERN. The photon requirement reduces the multijet background, and the H→bb¯ decay is the dominant decay mode. Event selection requirements target events produced by vector-boson fusion, the dominant production mode in this channel. Several improvements enhance the search sensitivity compared to previous measurements. These improvements include better background modelling and characterization, the use of a neural-network classifier, and an updated signal extraction strategy adopting a direct binned-likelihood fit to the classifier output. With these improvements, the Higgs boson signal strength is measured to be 0.2 ± 0.7 relative to the Standard Model prediction. This corresponds to an observed significance of 0.3 standard deviations, compared to an expectation of 1.5 standard deviations assuming the Standard Model.
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Journal articleChekhovsky V, Hayrapetyan A, Makarenko V, et al., 2026,
Search for dark matter production in association with bottom quarks and a lepton pair in proton-proton collisions at s=13 TeV
, Journal of High Energy Physics, Vol: 2026A search is performed for dark matter produced in association with bottom quarks and a pair of electrons or muons in data collected with the CMS detector at the LHC, corresponding to 138 fb<sup>−1</sup> of integrated luminosity of proton-proton collisions at a center-of-mass energy of 13 TeV. For the first time at the LHC, the associated production of a bottom quark-antiquark pair and a new heavy neutral Higgs boson (H) that subsequently decays into a leptonically decaying Z boson and a pseudoscalar (a) is explored. The latter acts as a dark matter mediator in the context of the two Higgs doublet model plus a pseudoscalar (2HDM+a). Multivariate techniques that target a wide range of mass configurations for the H and a particles are used. The observations are consistent with the expectations from standard model processes. Upper limits at 95% confidence level are set on the product of cross section and branching fraction of the new particles, ranging from 10<sup>−2</sup> pb for an H mass of 400 GeV to 10<sup>−3</sup> pb for an H mass of 2000 GeV. Constraints on the parameter space of a benchmark 2HDM+a model are derived and compared with expectations in the context of cosmological predictions.
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