Results
- Showing results for:
- Reset all filters
Search results
-
Journal articleAbe K, Abe S, Akutsu R, et al., 2025,
Results from the T2K Experiment on Neutrino Mixing Including a New Far Detector μ-like Sample.
, Phys Rev Lett, Vol: 135We have made improved measurements of three-flavor neutrino mixing with 19.7(16.3)×10^{20} protons on target in (anti-)neutrino-enhanced beam modes. A new sample of muon-neutrino events with tagged pions has been added at the far detector, as well as new proton and photon-tagged samples at the near detector. Significant improvements have been made to the flux and neutrino interaction modeling. T2K data continue to prefer the normal mass ordering and upper octant of sin^{2}θ_{23} with a near-maximal value of the charge-parity violating phase with best-fit values in the normal ordering of δ_{CP}=-2.18_{-0.47}^{+1.22}, sin^{2}θ_{23}=0.559_{-0.078}^{+0.018} and Δm_{32}^{2}=(+2.506_{-0.052}^{+0.039})×10^{-3} eV^{2}.
-
Journal articleChekhovsky V, Hayrapetyan A, Makarenko V, et al., 2025,
Observation of Coherent ϕ(1020) Meson Photoproduction in Ultraperipheral PbPb Collisions at sqrt[s_{NN}]=5.36 TeV.
, Phys Rev Lett, Vol: 135The first observation of coherent ϕ(1020) meson photoproduction off heavy nuclei is presented using ultraperipheral lead-lead collisions at a center-of-mass energy per nucleon pair of 5.36 TeV. The data were collected by the CMS experiment and correspond to an integrated luminosity of 1.62 μb^{-1}. The ϕ(1020) meson signals are reconstructed via the K^{+}K^{-} decay channel. The production cross section is presented as a function of the ϕ(1020) meson rapidity in the range 0.3<|y|<1.0, probing gluons that carry a fraction of the nucleon momentum (x) around 10^{-4}. The observed cross section exhibits little dependence on rapidity and is significantly suppressed, by a factor of ∼5, compared to a baseline model that treats a nucleus as a collection of free nucleons. Theoretical models that incorporate the nuclear shadowing effect generally provide a better description of the ϕ(1020) data than those incorporating gluon saturation. This study establishes a powerful new tool for exploring nuclear effects and nuclear gluonic structure in the small-x regime at a unique energy scale bridging the perturbative and nonperturbative quantum chromodynamics domains.
-
Journal articleAaij R, Abdelmotteleb ASW, Abellan Beteta C, et al., 2025,
First Observation of the Charmless Baryonic Decay B^{+}→Λ[over ¯]pp[over ¯]p.
, Phys Rev Lett, Vol: 135A search for the charmless baryonic decay B^{+}→Λ[over ¯]pp[over ¯]p is performed using proton-proton collision data recorded by the LHCb experiment, corresponding to an integrated luminosity of 5.4 fb^{-1}. The branching fraction for this decay is measured for the first time relative to that of the topologically similar decay B^{+}→J/ψK^{+}, with J/ψ→Λ[over ¯]pK^{-}. The branching fraction is measured to be B(B^{+}→Λ[over ¯]pp[over ¯]p)=(2.15±0.35±0.12±0.28)×10^{-7}, where the first uncertainty is statistical, the second is systematic, and the third arises from the uncertainty in the normalization channel branching fraction. The CP asymmetry is measured to be A_{CP}=(5.4±15.6±2.4)%, where the uncertainties are statistical and systematic. The background-subtracted invariant-mass distributions of Λ[over ¯]p and p[over ¯]p pairs exhibit pronounced enhancements at both kinematic thresholds, in contrast to a uniform phase-space distribution.
-
Conference paperSeikh MFH, Besson D, Giri P, et al., 2025,
Techniques for Continuous Wave Identification and Filtering in the Askaryan Radio Array
The Askaryan Radio Array (ARA), located near the geographical South Pole, is among the first experiments at the South Pole designed to detect ultra-high energy neutrinos through the Askaryan effect. When such neutrinos interact within dense media such as ice, they initiate particle cascades that, as they evolve, generate coherent radio pulses. Operating in the 150–850 MHz frequency band, ARA is deployed 80–200 meters deep in Antarctic ice, where the radio frequency background is exceptionally low. Despite the low background, experiments such as ARA must still account for continuous wave (CW) signals, which can originate from anthropogenic sources, instrumental noise, and other environmental factors. These CW signals can potentially obscure the faint neutrino-induced radio pulses, complicating data analysis and event identification. Over the years, ARA has developed and refined a number of techniques for CW filtering and identification, including spectral analysis, notch filtering, and phase-variance methods. These approaches exploit the unique characteristics of CW signals, such as their narrowband nature and temporal persistence, to effectively separate CW contamination from genuine impulsive events. We review the main CW identification and filtering techniques developed within the ARA collaboration and present recent improvements in their adaptive, multi-stage filtering pipelines. These advances have led to faster processing, easier operation, and more accurate CW identification and suppression, improving the consistency and quality of data analysis. The efficacy of these methods is demonstrated through CW identification and filtering for all ARA stations, showcasing their critical role in reducing event misclassification and improving the experiment’s overall performance. By refining these techniques, this work not only improves the sensitivity and data analysis performance of ARA, but also underscores the importance of robust CW identification
-
Conference paperAbarr Q, Allison P, Alvarez-Muñiz J, et al., 2025,
The Payload for Ultrahigh Energy Observations (PUEO): Detector Design and Implementation
The Payload for Ultrahigh Energy Observations (PUEO) is slated to fly in December of this year out of McMurdo Station in Antarctica in search of the highest energy neutrinos produced in our Universe. PUEO is designed to detect Askaryan emission, a broadband radio signal that occurs when a neutrino interacts in a dense dielectric medium like Antarctic ice. To achieve better sensitivity than ANITA, its predecessor, PUEO has redesigned its antennas and trigger to benefit from the advanced beamforming capabilities of the RF-System on Chip (RFSoC). PUEO will fly with two instruments: the main instrument, targeting the Askaryan emission from ultra-high energy neutrino flux, and the low frequency instrument, targeting radio emission from air showers induced by cosmic rays and tau neutrinos. Each detector is being carefully designed and modeled to maximize the potential sensitivity to these cosmic events. In this contribution, I will discuss the status of the PUEO instrument, which is currently undergoing integration and testing in advance of its upcoming 30-day mission. In particular, I will present our current expectations for hardware performance, our implementation of a drop-down Low Frequency Instrument, and our final areas of development prior to the flight. Finally, I will report on our simulation package, PUEOSim, and our progress towards modeling our instrument to prepare for both PUEO’s launch and for future analyses.
-
Conference paperAli S, Besson DZ, Alden N, et al., 2025,
Study of an Isolated Double-pulse Cosmic Ray Candidate Recorded with the Askaryan Radio Array
The radio-frequency emissions produced by particle showers on Earth, resulting from cosmic rays (CRs) and ultra-high energy neutrinos (UHE-ν) originating from astrophysical sources share significant similarities, enabling radio detectors initially designed for UHE-ν searches to also study CRs. The Askaryan Radio Array (ARA), an experiment currently operating within the ice at the South Pole, is primarily designed to detect UHE-νs. To date, ARA has deployed five stations, with each station equipped with antennas installed at depths up to 200 meters in the ice. Data recorded by ARA Station-2 (A2) suggest a potential CR origin for a subset of events identified in a UHEν search. This subset includes a double-pulse event potentially from a downward propagating CR-induced air shower, with in-air geomagnetic emission followed by in-ice Askaryan emission producing the two pulses. A detailed investigation of this CR candidate event using comprehensive simulations has been conducted with the goal of identifying the parameters of a CR-induced air shower that best match the experimentally observed quantities. We simulate predicted CR signals in ARA by combining an impacting CR shower simulation framework (FAERIE) with a realistic detector simulation (AraSim). We determine the event topology based on the vertex reconstruction of both the putative geomagnetic and Askaryan signals. After inferring the event geometry, we show that the simulation matches the observed time structure of the event (channel-by-channel relative signal arrival times) for the recorded event.
-
Conference paperAlden N, Ali S, Allison P, et al., 2025,
First Array-Wide Search for Diffuse UHE Neutrinos with the Askaryan Radio Array
The Askaryan Radio Array (ARA) is an ultrahigh energy (UHE) neutrino detector at the South Pole, designed to search for radio pulses emitted by neutrino-initiated particle showers in ice. ARA consists of an array of five autonomous stations with 2 km spacing. Each station consists of 16 radio antennas embedded ∼200 m deep in the ice that are sensitive to either vertically- or horizontally-polarized signals. Radio arrays like ARA represent a cost-efficient means of achieving the enormous detection O(10 km<sup>3</sup>) volumes necessary for UHE neutrino detection. This contribution presents the current status of the first-ever array-wide search for UHE neutrinos, leveraging ARA’s unprecedented ∼28 station-years of livetime. This search will have the best sensitivity of any neutrino detector above 3 EeV, sufficient to probe the 220 PeV flux inferred from KM3NeT’s observation of KM3-230213A. Importantly, this study demonstrates the feasibility of array-wide neutrino searches, which are necessary for next-generation detectors, like RNO-G (35 stations planned) and IceCube-Gen2 Radio (361 stations proposed), to achieve their design sensitivity. We discuss the progress towards a fully analyzed sample and improvements to ARA’s detector characterization and analysis sensitivity.
-
Conference paperAbarr Q, Allison P, Alvarez-Muñiz J, et al., 2025,
Neutrino Flavor Identification at the Highest Energies with PUEO
PUEO (the Payload for Ultra-high Energy Observations) is an Antarctic, balloon-borne experiment that aims to detect neutrinos above EeV energies primarily by searching for Askaryan radiation sourced from particle cascades induced by interactions within the ice. At the highest energies, neutrinos predominantly undergo charged-current interactions, producing high energy charged leptons which can induce secondary cascades during their propagation. PUEO is particularly sensitive to these secondary cascades for 2 reasons: i) high altitude observations provide long distances (O(100km)) to observed radiation, ensuring similar angles to the payload. This geometry allows for multi-pulse topology to occur readily within single detection windows ii) the pulse shape produced by Askaryan emission is dependent on interaction type (hadronic/electromagnetic/hybrid) and differentiation can point to charged-lepton flavor identification. In this talk, we discuss PUEO’s ability to measure and characterize secondary cascades in ice, moving towards a robust method for neutrino flavor identification at the highest energies. We also discuss how PUEO’s characterization of these secondary cascades helps to constrain neutrino energy and direction, both of which are crucial for multi-messenger based observations.
-
Conference paperMcBride K, Abarr Q, Allison P, et al., 2025,
Design of the Payload for Ultrahigh Energy Observations
Ultrahigh-energy cosmic rays (UHECR) should produce ultrahigh-energy neutrinos (UHEN) as byproducts of their propagation. Many candidate UHECR source models also predict an emission of UHEN local to their acceleration sites. The Payload for Ultrahigh Energy Observations (PUEO) is a balloon-borne observatory that will scan the Antarctic ice for these UHEN through their Askaryan emission and is the successor to the ANtarctic Impulsive Transient Antenna (ANITA). The payload design is optimized to detect these Askaryan signals with wide bandwidth measurements of dual-polarized antennas. The challenge in reaching high neutrino sensitivity includes outfitting many low-noise channels with linear polarization measurements and efficient filtering of backgrounds with size, power, and weight constraints to fit on a balloon-borne instrument. This poster will present the antennas, filtering, and data acquisition system in the context of meeting the science requirements of the PUEO mission.
-
Conference paperAbarr Q, Allison P, Alvarez-Muñiz J, et al., 2025,
Searching for Ultrahigh Energy Neutrinos with PUEO
PUEO, the Payload for Ultrahigh Energy Observations, is a long duration balloon-borne experiment with the primary science goal of detecting the impulsive Askaryan emission from ultrahigh energy (UHE, >1 EeV) neutrinos interacting in the ice sheet of Antarctica. The ultrahigh energy neutrino flux is yet to be detected, and so a successful measurement by PUEO will give us information about the where and how these neutrinos are produced; this may be through a process called the GZK effect when ultrahigh energy cosmic rays interact with the cosmic microwave background, or it may be directly within the environment of cosmic ray accelerators. In order to detect radio Askaryan emission, PUEO consists of a broadband interferometric radio detector of 96 antennas which point down at the ice. Additionally, it has a drop-down low-frequency subsystem which will deploy after launch. This improves PUEO’s ability to detect tau neutrinos and charged cosmic rays, which can both produce geomagnetic air shower emission. This contribution will outline PUEO’s science case, present its expected sensitivity, and share status updates from our preparation to launch PUEO from McMurdo Station, Antarctica in December 2025.
-
Conference paperAli S, Besson DZ, Alden N, et al., 2025,
First Ultra High Energy Neutrino Search with a Hybrid Phased and Traditional Detector in the Askaryan Radio Array
The Askaryan Radio Array (ARA) is an in-ice ultrahigh energy (UHE, >10 PeV) neutrino experiment at the South Pole, designed to detect neutrino-induced radio emission in ice. It consists of five independent stations, each featuring a cubic lattice of in-ice antenna clusters spaced 30 m apart and buried 200 m below the surface. The fifth ARA station (A5) is unique due to its central phased array string, which employs an interferometric trigger to enhance sensitivity to weak signals otherwise buried in noise. This low-threshold trigger makes ARA the first in-ice radio neutrino experiment to demonstrate a significant improvement in detecting low signal-to-noise ratio (SNR) radio signals. We present progress toward the first UHE neutrino search utilizing A5’s hybrid detection capability, incorporating advancements in data selection and background rejection. This analysis is the first to fully apply dedicated event selection to both components of ARA’s hybrid detector, improving directional reconstruction and significantly enhancing background rejection compared to previous analyses. This approach paves the way for next-generation in-ice UHE neutrino experiments.
-
Conference paperAlden N, Ali S, Allison P, et al., 2025,
Advancing ARA: the Next-Generation (ARA-Next) DAQ System
The Askaryan Radio Array (ARA) has been operating at the South Pole for over a decade, searching for ultra-high-energy astrophysical and cosmogenic neutrinos using the Askaryan effect. ARA has consistently served as a testbed for innovative trigger designs and advancing electronic upgrades, with ongoing data acquisition (DAQ) improvements over the past 2–3 years and a long-term plan to transition to Radio Frequency System-on-Chip (RFSoC) technology. This upgrade enables real-time data processing and sophisticated triggers, enhancing efficiency by identifying double pulses from in-ice neutrino interactions, using templates for cosmic rays, searching for real-time coincidences with the IceCube detector observations, and filtering anthropogenic noise through directional analysis. In 2024, two of the five ARA stations received DAQ upgrades, improving the existing electronics, with RFSoC-based DAQ foreseen in the coming years. In this proceedings contribution, recent ARA activities are presented, with emphasis on the planned ARA-Next trigger strategies involving RFSoC technology and the 2024–2025 season upgrades of the existing ATRI-based DAQ system to its revised version.
-
Conference paperWindischhofer P, Alden N, Alden N, et al., 2025,
Observation of Broadband In-ice Radiation from Impacting High-Energy Cosmic Rays
We present the first experimental evidence for in-ice radiofrequency emission from high-energy particle cascades developing in the Antarctic ice sheet. In 208 days of data recorded with the phased-array trigger of the Askaryan Radio Array, we detect 13 events with impulsive radiofrequency pulses originating from below the ice surface. Considering only the arrival angles and timing properties, this rate is inconsistent with an a-posteriori background expectation for thermal noise events and on-surface events at the level of 3.5 σ, which rises to 5.1 σ when additionally considering impulsivity. The observed event geometry, event rate, signal shape, spectral content, and electric field polarization are consistent with Askaryan radiation from cosmic ray air shower cores impacting the ice sheet. For the brightest events, the angular radiation pattern independently favors an extended cascade-like emitter over a pointlike source.
-
Conference paperAli S, Besson DZ, Alden N, et al., 2025,
High-Fidelity Simulations of the Full Askaryan Radio Array and its Sensitivity to Ultra-High Energy Neutrinos
The Askaryan Radio Array (ARA) is a five-station, in-ice radio detector located at the South Pole searching for particle cascades from cosmogenic and astrophysical neutrinos with ≥ 10<sup>17</sup> eV of energy. Cascades in this energy regime emit radio-wavelength Askaryan radiation that can be observed by one or more ARA stations. With the recent KM3Net observation of an approximately 220 PeV neutrino, there is renewed, urgent interest in further unlocking the ultra-high energy neutrino sky. We present updated calculations of ARA’s array-wide effective volume, sensitivity, and expected event rates for ultra-high energy neutrino-induced cascades. Notably, results now account for the contributions of secondary particles from neutrino interactions (such as muon tracks) and multi-station detections within a detailed detector simulation framework. Previous work has shown these secondary interactions and multi-station coincidences compose 25% and 8% of the detector’s effective area, respectively. We intend to extend these results towards a novel analysis that estimates the degree to which secondary cascades and multi-station observations are detectable in a real neutrino search. This will inform future UHE neutrino searches as it will characterize the feasibility of detecting such events.
-
Journal articleChekhovsky V, Hayrapetyan A, Makarenko V, et al., 2025,
General search for supersymmetric particles in scenarios with compressed mass spectra using proton-proton collisions at √¯s = 13 TeV
, Physical Review D, Vol: 112, Pages: 1-52, ISSN: 2470-0010A general search is presented for supersymmetric particles (sparticles) in scenarios featuring compressed mass spectra using proton-proton collisions at a center-of-mass energy of 13 TeV, recorded with the CMS detector at the LHC. The analyzed data sample corresponds to an integrated luminosity of 138 fb−1. Awide range of potential sparticle signatures are targeted, including pair production of electroweakinos, sleptons, and top squarks. The search focuses on events with a high transverse momentum system from initial-stateradiation jets recoiling against a potential sparticle system with significant missing transverse momentum. Events are categorized based on their lepton multiplicity, jet multiplicity, number of b-tagged jets, and kinematic variables sensitive to the sparticle masses and mass splittings. The sensitivity extends to higher parent sparticle masses than previously probed at the LHC for production of pairs of electroweakinos, sleptons, and top squarks with mass spectra featuring small mass splittings (compressed mass spectra). The observed results demonstrate agreement with the predictions of the background-only model. Lower mass limits are set at 95% confidence level on production of pairs of electroweakinos, sleptons, and top squarks that extend to 325, 275, and 780 GeV, respectively, for the most favorable compressed mass regime cases.
-
Journal articleAaij R, Abdelmotteleb ASW, Beteta CA, et al., 2025,
Measurement of transverse Λ and (Formula Presented) hyperon polarization in pPb collisions at (Formula Presented) TeV
, Physical Review D, Vol: 112, Pages: 1-15, ISSN: 2470-0010The transverse polarization of Λ and (Formula Presented) hyperons is measured in pPb collisions collected by the LHCb experiment at a nucleon-nucleon center-of-mass energy of 5.02 TeV. The polarization is averaged over hyperon transverse momentum in the range 0.15 < p<inf>T</inf> < 6.00 GeV=c, and Feynman-x in the ranges 0.005 < x<inf>F</inf> < 0.040 (forward region) and −0.10 < x<inf>F</inf> < −0.01 (backward region) defined relative to the proton beam direction. The transverse polarization is found to be compatible with zero for both Λ and Λ̄ hyperons. The results are also measured as a function of p<inf>T</inf> and x<inf>F</inf> with no significant dependence on these variables observed. The results are compared with previous experimental measurements at different center-of-mass energies and collision environments.
-
Journal articleAbe K, Abe S, Akutsu R, et al., 2025,
Measurement of muon neutrino induced charged current interactions without charged pions in the final state using a new T2K off-axis near detector WAGASCI-BabyMIND
, Physical Review D, Vol: 112, ISSN: 2470-0010We report a flux-integrated cross section measurement of muon neutrino interactions on water and hydrocarbon via charged current reactions without charged pions in the final state with the WAGASCI-BabyMIND detector, which was installed in the T2K near detector hall in 2018. The detector is located 1.5° off-axis and is exposed to a more energetic neutrino flux than ND280, another T2K near detector, which is located at a different off-axis position. The total flux-integrated cross section is measured to be 1.26 ± 0.18(stat + syst) x 10<sup>-39</sup> cm<sup>2</sup>=nucleon on CH and 1.44 ± 0.21(stat + syst) x 10<sup>-39</sup> cm<sup>2</sup>=nucleon on H<inf>2</inf>O. These results are compared to model predictions provided by the NEUT v5.3.2 and GENIE v2.8.0 Monte Carlo generators and the measurements are compatible with these models. Differential cross sections in muon momentum and cosine of the muon scattering angle are also reported. This is the first such measurement reported with the WAGASCI-BabyMIND detector and utilizes the 2020 and 2021 datasets.
-
Journal articleAbratenko P, Andrade Aldana D, Arellano L, et al., 2025,
First Measurement of Charged-Current Muon-Neutrino-Induced K^{+} Production on Argon Using the MicroBooNE Detector.
, Phys Rev Lett, Vol: 135The MicroBooNE experiment is an 85 tonne active mass liquid argon time projection chamber neutrino detector exposed to the on-axis Booster Neutrino Beam at Fermilab. One of MicroBooNE's physics goals is the precise measurement of neutrino interactions on argon in the 1 GeV energy regime. Building on the capabilities of the MicroBooNE detector, this analysis identifies K^{+} mesons, a key signature for the study of strange particle production in neutrino interactions. This measurement is furthermore valuable for background estimation for future nucleon decay searches and for improved reconstruction and particle identification capabilities in experiments such as the Deep Underground Neutrino Experiment. In this Letter, we present the first-ever measurement of a flux-integrated cross section for charged-current muon neutrino induced K^{+} production on argon nuclei, determined to be 7.93±3.22(stat)±2.83(syst)×10^{-42} cm^{2}/nucleon based on an analysis of 6.88×10^{20} protons on target. This result was found to be consistent with model predictions from different neutrino event generators within the reported uncertainties.
-
Journal articleHayrapetyan A, Makarenko V, Tumasyan A, et al., 2025,
Search for charged lepton flavor violating <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"> <mml:mi>Z</mml:mi> </mml:math> and <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"> <mml:msup> <mml:mi>Z</mml:mi> <mml:mo>′</mml:mo> </mml:msup> </mml:math> boson decays in proton-proton collisions at <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"> <mml:msqrt> <mml:mi>s</mml:mi> </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:math>
, Physical Review D, Vol: 112, ISSN: 2470-0010<jats:p> A search for flavor violating decays of the <a:math xmlns:a="http://www.w3.org/1998/Math/MathML" display="inline"> <a:mi>Z</a:mi> </a:math> boson to charged leptons is performed using data from proton-proton collisions at <c:math xmlns:c="http://www.w3.org/1998/Math/MathML" display="inline"> <c:msqrt> <c:mi>s</c:mi> </c:msqrt> <c:mo>=</c:mo> <c:mn>13</c:mn> <c:mtext> </c:mtext> <c:mtext> </c:mtext> <c:mi>TeV</c:mi> </c:math> collected with the CMS detector at the LHC, corresponding to an integrated luminosity of <e:math xmlns:e="http://www.w3.org/1998/Math/MathML" display="inline"> <e:mn>138</e:mn> <e:mtext> </e:mtext> <e:mtext> </e:mtext> <e:msup> <e:mi>fb</e:mi> <e:mrow> <e:mo>−</e:mo> <e:mn>1</e:mn> </e:mrow> </e:msup> </e:math> . Each of the decays <g:math xmlns:g="http://www.w3.org/1998/Math/MathML" display="inline"> <g:mi>Z</g:mi> <g:mo stretchy="false">→</g:mo> <g:mi>e</g:mi>
-
Journal articleChekhovsky V, Hayrapetyan A, Makarenko V, et al., 2025,
Measurement of event shapes in minimum-bias events from proton-proton collisions at √s = 13 TeV
, Physical Review D, Vol: 112, ISSN: 2470-0010A measurement of event-shape variables is presented, using a data sample produced in a special run with approximately one inelastic proton-proton collision per bunch crossing. The data were collected with the CMS detector at a center-of-mass energy of 13 TeV, corresponding to an integrated luminosity of 64 μb<sup>−1</sup>. A number of observables related to the overall distribution of charged particles in the collisions are corrected for detector effects and compared with simulations. Inclusive event-shape distributions, as well as differential distributions of event shapes as functions of charged-particle multiplicity, are studied. None of the models investigated are able to satisfactorily describe the data. Moreover, there are significant features common amongst all generator setups studied, particularly showing data being more isotropic than any of the simulations. Multidimensional unfolded distributions are provided, along with their correlations.
-
Journal articleHayrapetyan A, Tumasyan A, Adam W, et al., 2025,
Search for New Physics in Jet Multiplicity Patterns of Multilepton Events at sqrt[s]=13 TeV.
, Phys Rev Lett, Vol: 135A first search for beyond the standard model physics in jet multiplicity patterns of multilepton events is presented, using a data sample corresponding to an integrated luminosity of 138 fb^{-1} of 13 TeV proton-proton collisions recorded by the CMS detector at the LHC. The search uses observed jet multiplicity distributions in one-, two-, and four-lepton events to explore possible enhancements in jet production rate in three-lepton events with and without bottom quarks. The data are found to be consistent with the standard model expectation. The results are interpreted in terms of supersymmetric production of electroweak chargino-neutralino superpartners with cascade decays terminating in prompt hadronic R-parity violating interactions.
-
Journal articleCollaboration TC, 2025,
Search for heavy pseudoscalar and scalar bosons decaying to a top quark pair in proton-proton collisions ats=13TeV.
, Rep Prog Phys, Vol: 88A search for pseudoscalar or scalar bosons decaying to a top quark pair (tt¯) in final states with one or two charged leptons is presented. The analyzed proton-proton collision data was recorded ats=13TeVby the CMS experiment at the CERN LHC and corresponds to an integrated luminosity of 138 fb-1. The invariant massmtt¯of the reconstructedtt¯system and variables sensitive to its spin and parity are used to discriminate against the standard modeltt¯background. Interference between pseudoscalar or scalar boson production and the standard modeltt¯continuum is included, leading to peak-dip structures in themtt¯distribution. An excess of the data above the background prediction, based on perturbative quantum chromodynamics (QCD) calculations, is observed near the kinematictt¯production threshold, while good agreement is found for highmtt¯. The data are consistent with the background prediction if the contribution from a simplified model of a color-singlet1S0[1]tt¯quasi-bound stateηt, inspired by nonrelativistic QCD, is added. Upper limits at 95% confidence level are set on the coupling between the pseudoscalar or scalar bosons and the top quark for boson masses in the range 365-1000 GeV, relative widths between 0.5% and 25%, and two background scenarios with or withoutηtcontribution.
-
Journal articleAaij R, Abdelmotteleb ASW, Abellan Beteta C, et al., 2025,
Observation of Orbitally Excited B_{c}^{+} States.
, Phys Rev Lett, Vol: 135The observation of a wide peaking structure in the B_{c}^{+}γ mass spectrum is reported using proton-proton collision data collected by the LHCb detector at center-of-mass energies of 7, 8, and 13 TeV, corresponding to a total integrated luminosity of 9 fb^{-1}. The statistical significance over the background-only hypothesis exceeds seven standard deviations. The width of the observed structure is larger than the expectation from a single-peak hypothesis, and is well described by an effective minimal model consisting of two narrow peaks located at 6704.8±5.5±2.8±0.3 MeV/c^{2} and 6752.4±9.5±3.1±0.3 MeV/c^{2}. The uncertainty terms are statistical, systematic, and associated to the knowledge of the B_{c}^{+} mass, respectively. The measured peak locations are in line with theoretical predictions for lowest excited P-wave B_{c}^{+} states, marking the first observation of orbitally excited beauty-charm mesons and providing important insights into the internal dynamics of hadrons containing two heavy quarks.
-
Journal articleHayrapetyan A, Tumasyan A, Adam W, et al., 2025,
Determination of the spin and parity of all-charm tetraquarks
, NATURE, Vol: 648, Pages: 58-+, ISSN: 0028-0836 -
Journal articleAbratenko P, Alterkait O, Andrade Aldana D, et al., 2025,
Measurement of single- and double-differential cross sections for mesonless charged-current muon neutrino interactions on argon with final-state protons using the MicroBooNE detector
, Dizhi Xuebao Acta Geologica Sinica, Vol: 92, Pages: 1-43, ISSN: 0001-5717Charged-current neutrino interactions with final states containing zero mesons and at least one proton are of high interest for current and future accelerator-based neutrino oscillation experiments. Using the Booster Neutrino Beam and the MicroBooNE detector at Fermi National Accelerator Laboratory, we have obtained the first double-differential cross-section measurements of this channel for muon neutrino scattering on an argon target with a leading proton momentum threshold of 0.25 GeV=c. We also report a flux-averaged total cross section of (Formula Presented) and several single-differential measurements which extend and improve upon previous results. Statistical and systematic uncertainties are quantified with a full treatment of correlations across 359 kinematic bins, including correlations between distributions describing different observables. The resulting dataset provides the most detailed information obtained to date for testing models of mesonless neutrino-argon scattering.
-
Journal articleAaij R, Abdelmotteleb ASW, Beteta CA, et al., 2025,
Study of Bc(1P)+ states in the (Formula Presented) mass spectrum
, Physical Review D, Vol: 112, Pages: 1-18, ISSN: 2470-0010The study of a wide peaking structure in the (Formula Presented) mass spectrum is reported using a data sample of proton-proton collisions collected by the LHCb detector at center-of-mass energies of 7, 8, and 13 TeV, corresponding to an integrated luminosity of 9 fb<sup>−1</sup>. The observed structure is consistent with the lowest excited P-wave B<sup>+</sup> <inf>c</inf> states and exhibits a statistical significance exceeding 7 standard deviations relative to the background-only hypothesis. A two-peak model serves as an effective description of the data, with various theory-constrained models further explored to provide physical interpretation. Based on the predictions for the B<inf>c</inf>(1P)<sup>+</sup> spectrum, the relative production cross section of the overall B<inf>c</inf>(1P)<sup>+</sup> states with respect to the (Formula Presented) ground state with the transverse momentum p<inf>T</inf> and rapidity y of (Formula Presented) mesons in the ffiffi regions p<inf>T</inf> < 20 GeV=c and 2.0 < y < 4.5 at (Formula Presented) is measured to be 0.20 ± 0.03 ± 0.02 ± 0.03, where the uncertainty terms represent statistical, systematic, and uncertainties related to the choice of theoretical models, respectively. The results provide a test of theoretical models and deepen our understanding of quantum chromodynamics.
-
Journal articleChekhovsky V, Hayrapetyan A, Makarenko V, et al., 2025,
Search for <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"> <mml:mi>γ</mml:mi> <mml:mi>H</mml:mi> </mml:math> production and constraints on the Yukawa couplings of light quarks to the Higgs boson
, Physical Review D, Vol: 112, ISSN: 2470-0010<jats:p> A search for <a:math xmlns:a="http://www.w3.org/1998/Math/MathML" display="inline"> <a:mi>γ</a:mi> <a:mi>H</a:mi> </a:math> production is performed with data from the CMS experiment at the LHC corresponding to an integrated luminosity of <c:math xmlns:c="http://www.w3.org/1998/Math/MathML" display="inline"> <c:mn>138</c:mn> <c:mtext> </c:mtext> <c:mtext> </c:mtext> <c:msup> <c:mi>fb</c:mi> <c:mrow> <c:mo>−</c:mo> <c:mn>1</c:mn> </c:mrow> </c:msup> </c:math> at a proton-proton center-of-mass collision energy of <e:math xmlns:e="http://www.w3.org/1998/Math/MathML" display="inline"> <e:mrow> <e:mn>13</e:mn> <e:mtext> </e:mtext> <e:mtext> </e:mtext> <e:mi>TeV</e:mi> </e:mrow> </e:math> . The analysis focuses on the topology of a boosted Higgs boson recoiling against a high-energy photon. The final states of <g:math xmlns:g="http://www.w3.org/1998/Math/MathML" display="inline"> <g:mi>H</g:mi> <g:mo stretchy="false">→</g:mo>
-
Journal articleKhan N, Hua Y, Xiotidis I, et al., 2025,
Readout electronics for low occupancy High-Pressure Gas TPCs
, Journal of Instrumentation, Vol: 20High-Pressure Gas Time Projection Chambers (HPgTPCs) have benefits such as low energy thresholds, magnetisability, and 4 acceptance, making them ideal for neutrino experiments such as DUNE. We present the design of an FPGA-based solution optimised for Gaseous Argon Near Detector (ND-GAr), which is part of the Phase-II more capable near detector for DUNE. These electronics reduce the cost significantly compared to using collider readout electronics, which are typically designed for much higher occupancy and therefore, for example, need much larger numbers of FPGAs and power per channel. We demonstrate the performance of our electronics with the Teststand for an Overpressurised Argon Detector (TOAD) at Fermilab in the US at a range of pressures and gas mixtures up to 4.5 barA, reading out ∼10 000 channels from a Multi-Wire Proportional Chamber (MWPC). The operation took place between April and July of 2024. We measure the noise characteristics of the system to be sufficiently low, and we identify sources of noise that can be further mitigated in the next iteration. We also note that the cooling scheme used in the test requires improvement before full-scale deployment. Despite these necessary improvements, we show that the system can fulfil the needs of a HPgTPC for a fraction of the price of collider readout electronics.
-
Journal articleZamora-Saá JA, Abbaneo D, Ahmad S, et al., 2025,
The SND@LHC collaboration
, Journal of Instrumentation, Vol: 20This paper presents the design, construction, and simulation-based validation of the ColdBox, a combined neutron shielding and insulating enclosure for the Scattering and Neutrino Detector at the LHC (SND@LHC). The emulsion films in the detector’s target region require protection from the intense neutron radiation background and a stable environment of 15 ± 1 <sup>◦</sup>C and 50–55 % relative humidity for long-term stability. The ColdBox meets these requirements through a dual-layer structure: an external 5 cm plexiglass wall to moderate fast neutrons, and an internal 4 cm layer of borated polyethylene (with 35 % boron content) to capture thermal neutrons. The mechanical design, based on a robust aluminum frame, accommodates the constraints of the TI18 tunnel. FLUKA simulations were used to optimize the shielding configuration, showing a significant reduction in the neutron flux, with a simulated ratio of shielded to unshielded thermal neutron fluence of 2.3 × 10<sup>−3</sup>. This result is consistent with initial measurements from BatMon detectors. The design also provides a sealed volume for a cooling system to maintain the required temperature and humidity, ensuring the necessary conditions for the emulsion films’ integrity.
-
Journal articleBenedikt M, Zimmermann F, Auchmann B, et al., 2025,
Future circular collider feasibility study report: Volume 2 Accelerators, technical infrastructure and safety
, European Physical Journal Special Topics, Vol: 234, Pages: 5713-6197, ISSN: 1951-6355In response to the 2020 Update of the European Strategy for Particle Physics, the Future Circular Collider (FCC) Feasibility Study was launched as an international collaboration hosted by CERN. This report describes the FCC integrated programme, which consists of two stages: an electron-positron collider (FCC-ee) in the first phase, serving as a high-luminosity Higgs, top, and electroweak factory; followed by a proton-proton collider (FCC-hh) at the energy frontier in the second phase. The FCC-ee is designed to operate at four key centre-of-mass energies: the Z pole, the WW pair production threshold, the ZH production peak, and the top/anti-top production threshold—each delivering the highest possible luminosities to four experiments. Over 15 years of operation, FCC-ee will produce more than 6 trillion Z bosons, 200 million WW pairs, nearly 3 million Higgs bosons, and 2 million top anti-top pairs. Precise energy calibration at the Z pole and WW threshold will be achieved through frequent resonant depolarisation of pilot bunches. The sequence of operation modes between the Z, WW, and ZH substages remains flexible. The FCC-hh will operate at a centre-of-mass energy of approximately 85 TeV—nearly an order of magnitude higher than the LHC—and is designed to deliver 5 to 10 times the integrated luminosity of the upcoming High-Luminosity LHC. Its mass reach for direct discovery extends to several tens of TeV. In addition to proton-proton collisions, the FCC-hh is capable of supporting ion-ion, ion-proton, and lepton-hadron collision modes. This second volume of the Feasibility Study Report presents the complete design of the FCC-ee collider, its operation and staging strategy, the full-energy booster and injector complex, required accelerator technologies, safety concepts, and technical infrastructure. It also includes the design of the FCC-hh hadron collider, development of high-field magnets, hadron injector options, and key technical systems for
This data is extracted from the Web of Science and reproduced under a licence from Thomson Reuters. You may not copy or re-distribute this data in whole or in part without the written consent of the Science business of Thomson Reuters.