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Journal articleHayrapetyan A, Tumasyan A, Adam W, et al., 2025,
Search for New Resonances Decaying to Pairs of Merged Diphotons in Proton-Proton Collisions at sqrt[s]=13 TeV.
, Phys Rev Lett, Vol: 134A search is presented for an extended Higgs sector with two new particles, X and ϕ, in the process X→ϕϕ→(γγ)(γγ). Novel neural networks classify events with diphotons that are merged and determine the diphoton masses. The search uses LHC proton-proton collision data at sqrt[s]=13 TeV collected with the CMS detector, corresponding to an integrated luminosity of 138 fb^{-1}. No evidence of such resonances is seen. Upper limits are set on the production cross section for m_{X} between 300 and 3000 GeV and m_{ϕ}/m_{X} between 0.5% and 2.5%, representing the most sensitive search in this channel.
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Journal articleAaij R, Abdelmotteleb ASW, Abellan Beteta C, et al., 2025,
Observation of Exotic J/ψϕ Resonant Structure in Diffractive Processes in Proton-Proton Collisions.
, Phys Rev Lett, Vol: 134The first study of J/ψϕ production in diffractive processes in proton-proton collisions is presented. The study is based on an LHCb dataset recorded at center-of-mass energy of 13 TeV, corresponding to an integrated luminosity of 5 fb^{-1}. The data disfavor a nonresonant J/ψϕ production but are consistent with a resonant model including several resonant states observed previously only in B^{+}→J/ψϕK^{+} decays. The χ_{c0}(4500) state is observed with a significance over 6σ and the χ_{c1}(4274) is confirmed with a significance of more than 4σ.
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Journal articleHayrapetyan A, Tumasyan A, Adam W, et al., 2025,
Measurement of inclusive and differential cross sections of single top quark production in association with a W boson 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 first measurement of the inclusive and normalised differential cross sections of single top quark production in association with a W boson in proton-proton collisions at a centre-of-mass energy of 13.6 TeV is presented. The data were recorded with the CMS detector at the LHC in 2022, and correspond to an integrated luminosity of 34.7 fb<jats:sup> <jats:italic>−</jats:italic>1</jats:sup>. The analysed events contain one muon and one electron in the final state. For the inclusive measurement, multivariate discriminants exploiting the kinematic properties of the events are used to separate the signal from the dominant top quark-antiquark production background. A cross section of <jats:inline-formula> <jats:alternatives> <jats:tex-math>$$ 82.3\pm 2.1{\left(\textrm{stat}\right)}_{-9.7}^{+9.9}\left(\textrm{syst}\right)\pm 3.3\left(\textrm{lumi}\right) $$</jats:tex-math> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mn>82.3</mml:mn> <mml:mo>±</mml:mo> <mml:mn>2.1</mml:mn> <mml:msubsup> <mml:mfenced> <mml:mtext>stat</mml:mtext> </mml:mfenced> <mml:mrow> <mml:mo>−</mml:mo> <mml:mn>9.7</mml:mn> </mml:mrow> <mml:mrow> <mml:mo>+</mml:mo> <mml:mn>9.9</mml:mn> </mml:mrow> </mml:msubsup> <mml:mfenced> <mml:mtext>syst</mml:mtex
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Journal articleAhmed A, Bhattacharya A, Das I, 2025,
Anomalous and large topological Hall effects inβ-Mn chiral compound Co6.5Ru1.5Zn8Mn4: electron electron interaction facilitated quantum interference effect.
, J Phys Condens Matter, Vol: 37β-Mn-type chiral cubic CoxZnyMnz(x+y+z= 20) alloys present a intriguing platform for exploring topological magnetic orderings with promising spintronic potential. This study examines the magnetotransport properties of Co6.5Ru1.5Zn8Mn4, a skyrmion-hostingβ-Mn-type chiral compound. The longitudinal resistivity (ρxx) exhibits field-insensitive low-temperature minima due to quantum interference effects, driven byT1/2-dependent electron-electron interactions. We observe a substantial intrinsic anomalous Hall conductivity, unaffected by quantum interference. Additionally, a pronounced topological Hall effect is observed at the metastable skyrmionic state, persisting up toTCand achieving notable magnitudes for stoichiometric compounds. These results position the CoxZnyMnzfamily favourably to leverage the rich pallete of emergent magnetotransport properties for spintronic applications.
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Journal articleAbe K, Abe S, Bronner C, et al., 2025,
First Joint Oscillation Analysis of Super-Kamiokande Atmospheric and T2K Accelerator Neutrino Data.
, Phys Rev Lett, Vol: 134The Super-Kamiokande and T2K Collaborations present a joint measurement of neutrino oscillation parameters from their atmospheric and beam neutrino data. It uses a common interaction model for events overlapping in neutrino energy and correlated detector systematic uncertainties between the two datasets, which are found to be compatible. Using 3244.4 days of atmospheric data and a beam exposure of 19.7(16.3)×10^{20} protons on target in (anti)neutrino mode, the analysis finds a 1.9σ exclusion of CP conservation (defined as J_{CP}=0) and a 1.2σ exclusion of the inverted mass ordering.
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Journal articleZhokin A, Zhizhin I, Zarubin A, et al., 2025,
Measurement of multidifferential cross sections for dijet production in proton–proton collisions at s=13TeV
, European Physical Journal C, Vol: 85, ISSN: 1434-6044A measurement of the dijet production cross section is reported based on proton–proton collision data collected in 2016 at s=13TeV by the CMS experiment at the CERN LHC, corresponding to an integrated luminosity of up to 36.3fb-1. Jets are reconstructed with the anti-kT algorithm for distance parameters of R=0.4 and 0.8. Cross sections are measured double-differentially (2D) as a function of the largest absolute rapidity |y|max of the two jets with the highest transverse momenta pT and their invariant mass m1,2, and triple-differentially (3D) as a function of the rapidity separation y∗, the total boost yb, and either m1,2 or the average pT of the two jets. The cross sections are unfolded to correct for detector effects and are compared with fixed-order calculations derived at next-to-next-to-leading order in perturbative quantum chromodynamics. The impact of the measurements on the parton distribution functions and the strong coupling constant at the mass of the Z boson is investigated, yielding a value of αS(mZ)=0.1179±0.0019.
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Journal articleAhmed A, Sharma J, Bhattacharya A, et al., 2025,
Unconventional Anomalous Hall Effect in Hexagonal Polar Magnet Y3Co8Sn4
, Advanced Functional Materials, ISSN: 1616-301XA rare realization of unconventional anomalous Hall effect (UAHE) both below and above the magnetic transition temperature (T<inf>C</inf>) in a hexagonal noncentrosymmetric magnet Y<inf>3</inf>Co<inf>8</inf>Sn<inf>4</inf>, using a combined experimental and ab initio calculations. Occurrence of such UAHE is mainly attributed to the reciprocal ((Formula presented.)) topology (i.e., the presence of topological Weyl points at/near the Fermi level), along with some contribution from the topological magnetic texture (at low temperatures), as inferred from the measured field-dependent ac susceptibility. The effect of UAHE on the measured transport behavior however evolves differently with temperature above and below T<inf>C</inf> = 53 K, suggesting different physical mechanism responsible in the two phases. A unique planar ferrimagnetic ordering is found to be the most stable state with ab-plane as the easy plane below T<inf>C</inf>. The simulated net magnetization and the moment per Co atom agrees fairly well with the experimentally measured values. A reasonably large anomalous Hall conductivity (AHC) is also observed in both the phases (above and below T<inf>C</inf>) of the present compound, which is again not so ubiquitous. The results underscore the family of R<inf>3</inf>Co<inf>8</inf>Sn<inf>4</inf> (R = rare earth) polar magnets as a compelling backdrop for exploring the synergy of magnetism and topological non-trivial electronic states, pivotal for spintronic applications.
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Journal articleHayrapetyan A, Tumasyan A, Adam W, et al., 2025,
Search for charged-lepton flavor violation in the production and decay of top quarks using trilepton final states in proton-proton collisions at (Formula presented)
, Physical Review D, Vol: 111, ISSN: 2470-0010A search is performed for charged-lepton flavor violating processes in top quark ((Formula presented)) production and decay. The data were collected by the CMS experiment from proton-proton collisions at a center-of-mass energy of 13 TeV and correspond to an integrated luminosity of (Formula presented). The selected events are required to contain one opposite-sign electron-muon pair, a third charged lepton (electron or muon), and at least one jet of which no more than one is associated with a bottom quark. Boosted decision trees are used to distinguish signal from background, exploiting differences in the kinematics of the final states particles. The data are consistent with the standard model expectation. Upper limits at 95% confidence level are placed in the context of effective field theory on the Wilson coefficients, which range between (Formula presented) depending on the flavor of the associated light quark and the Lorentz structure of the interaction. These limits are converted to upper limits on branching fractions involving up (charm) quarks, (Formula presented) ((Formula presented)), of (Formula presented), (Formula presented), and (Formula presented) for tensorlike, vectorlike, and scalarlike interactions, respectively.
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Journal articleHayrapetyan A, Tumasyan A, Adam W, et al., 2025,
Search for bottom quark associated production of the standard model Higgs boson in final states with leptons in proton-proton collisions at s=13TeV
, Physics Letters Section B Nuclear Elementary Particle and High Energy Physics, Vol: 860, ISSN: 0370-2693This Letter presents the first search for bottom quark associated production of the standard model Higgs boson, in final states with leptons. Higgs boson decays to pairs of tau leptons and pairs of leptonically decaying W bosons are considered. The search is performed using data collected from 2016 to 2018 by the CMS experiment in proton-proton collisions at a centre-of-mass energy of 13 TeV, corresponding to an integrated luminosity of 138fb<sup>−1</sup>. Upper limits at the 95% confidence level are placed on the signal strength for Higgs boson production in association with bottom quarks; the observed (expected) upper limit is 3.7 (6.1) times the standard model prediction.
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Journal articleAaij R, Abdelmotteleb ASW, Abellan Beteta C, et al., 2025,
Measurement of D0- D ¯ 0 mixing and search for CP violation with D0 →k+π- decays
, Physical Review D, Vol: 111, ISSN: 2470-0010A measurement of the time-dependent ratio of the D0→K+π- to D¯0→K+π- decay rates is reported. The analysis uses a sample of proton-proton collisions corresponding to an integrated luminosity of 6 fb-1 recorded by the LHCb experiment from 2015 through 2018 at a center-of-mass energy of 13 TeV. The D0 meson is required to originate from a D∗(2010)+→D0π+ decay, such that its flavor at production is inferred from the charge of the accompanying pion. The measurement is performed simultaneously for the K+ π- and K- π+ final states, allowing both mixing and CP-violation parameters to be determined. The value of the ratio of the decay rates at production is determined to be RKπ=(343.1±2.0)×10-5. The mixing parameters are measured to be cKπ=(51.4±3.5)×10-4 and cKπ′=(13±4)×10-6, where RKπcKπ is the linear coefficient of the expansion of the ratio as a function of decay time in units of the D0 lifetime, and cKπ′ is the quadratic coefficient, both averaged between the K+ π- and K- π+ final states. The precision is improved relative to the previous best measurement by approximately 60%. No evidence for CP violation is found.
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Journal articleHayrapetyan A, Tumasyan A, Adam W, et al., 2025,
Study of WH production through vector boson scattering and extraction of the relative sign of the W and Z couplings to the Higgs boson in proton-proton collisions at s=13TeV
, Physics Letters Section B Nuclear Elementary Particle and High Energy Physics, Vol: 860, ISSN: 0370-2693A search for the production of a W boson and a Higgs boson through vector boson scattering (VBS) is presented, using CMS data from proton-proton collisions at s=13TeV collected from 2016 to 2018. The integrated luminosity of the data sample is 138fb<sup>−1</sup>. Selected events must be consistent with the presence of two jets originating from VBS, the leptonic decay of the W boson to an electron or muon, possibly also through an intermediate τ lepton, and a Higgs boson decaying into a pair of b quarks, reconstructed as either a single merged jet or two resolved jets. A measurement of the process as predicted by the standard model (SM) is performed alongside a study of beyond-the-SM (BSM) scenarios. The SM analysis sets an observed (expected) 95% confidence level upper limit of 14.3 (9.9) on the ratio of the measured VBS WH cross section to that expected by the SM. The BSM analysis, conducted within the so-called κ framework, excludes all scenarios with λ<inf>WZ</inf><0 that are consistent with current measurements, where λ<inf>WZ</inf>=κ<inf>W</inf>/κ<inf>Z</inf> and κ<inf>W</inf> and κ<inf>Z</inf> are the HWW and HZZ coupling modifiers, respectively. The significance of the exclusion is beyond 5 standard deviations, and it is consistent with the SM expectation of λ<inf>WZ</inf>=1.
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Journal articleBarbone M, Howard A, Novak M, et al., 2025,
Application of computational modelling to particle physics
, Communications in computational physics, ISSN: 1991-7120 -
Journal articleHayrapetyan A, Tumasyan A, Adam W, et al., 2025,
Measurement of the double-differential inclusive jet cross section in proton-proton collisions at s = 5.02 TeV
, Journal of High Energy Physics, Vol: 2025The inclusive jet cross section is measured as a function of jet transverse momentum p<inf>T</inf> and rapidity y. The measurement is performed using proton-proton collision data at s = 5.02 TeV, recorded by the CMS experiment at the LHC, corresponding to an integrated luminosity of 27.4 pb<sup>−1</sup>. The jets are reconstructed with the anti-k<inf>T</inf> algorithm using a distance parameter of R = 0.4, within the rapidity interval |y| < 2, and across the kinematic range 0.06 < p<inf>T</inf>< 1 TeV. The jet cross section is unfolded from detector to particle level using the determined jet response and resolution. The results are compared to predictions of perturbative quantum chromodynamics, calculated at both next-to-leading order and next-to-next-to-leading order. The predictions are corrected for nonperturbative effects, and presented for a variety of parton distribution functions and choices of the renormalization/factorization scales and the strong coupling α<inf>S</inf>.
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Journal articleAaij R, Abdelmotteleb ASW, Abellan Beteta C, et al., 2025,
Measurement of CP violation in B0→ D+D− and Bs0→Ds+Ds− decays
, Journal of High Energy Physics, Vol: 2025A time-dependent, flavour-tagged measurement of CP violation is performed with B<sup>0</sup>→ D<sup>+</sup>D<sup>−</sup> and Bs0→Ds+Ds− decays, using data collected by the LHCb detector in proton-proton collisions at a centre-of-mass energy of 13 TeV corresponding to an integrated luminosity of 6 fb<sup>−1</sup>. In B<sup>0</sup>→ D<sup>+</sup>D<sup>−</sup> decays the CP-violation parameters are measured to be (Formula presented.) In Bs0→Ds+Ds− decays the CP-violating parameter formulation in terms of ϕ<inf>s</inf> and |λ| results in (Formula presented.) These results represent the most precise single measurement of the CP-violation parameters in their respective channels. For the first time in a single measurement, CP symmetry is observed to be violated in B<sup>0</sup>→ D<sup>+</sup>D<sup>−</sup> decays with a significance exceeding six standard deviations.
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Journal articleZunica G, Zuliani D, Zou Q, et al., 2025,
Long-lived particle reconstruction downstream of the LHCb magnet
, European Physical Journal C, Vol: 85, ISSN: 1434-6044Charged-particle trajectories are usually reconstructed with the LHCb detector using combined information from the tracking devices placed upstream and downstream of the 4 T m dipole magnet. Trajectories reconstructed using only information from the tracker downstream of the dipole magnet, which are referred to as T tracks, have not been used for physics analysis to date. The challenges of the reconstruction of long-lived particles with T tracks for physics use are discussed and solutions are proposed. The feasibility and the tracking performance are studied using samples of long-lived Λ and KS0 hadrons decaying between 6.0 and 7.6 m downstream of the proton–proton collision point, thereby traversing most of the magnetic field region and providing maximal sensitivity to magnetic and electric dipole moments. The reconstruction can be expanded upstream to about 2.5 m for use in direct searches of exotic long-lived particles. The data used in this analysis have been recorded between 2015 and 2018 and correspond to an integrated luminosity of 6 fb-1. The results obtained demonstrate the possibility to further extend the decay volume and the physics reach of the LHCb experiment.
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Journal articleKarikar A, Das K, Das I, 2025,
Magnetoresistive and magnetocaloric properties of polycrystalline Sm0.50Sr0.50MnO3 compound with short range magnetic ordering
, Journal of Materials Science Materials in Electronics, Vol: 36, ISSN: 0957-4522In this study, the magnetic and magneto-transport properties of polycrystalline Sm0.50Sr0.50MnO3 have been investigated. The presence of short-range magnetic order plays a crucial role in influencing electron transport, making it a promising pathway for tuning magnetoresistive properties for specific applications. This research focuses on the effects of magnetic nanoclusters on spin-dependent scattering and their impact on magneto-transport and magnetocaloric properties in polycrystalline Sm0.50Sr0.50MnO3. Experimental results reveal a significant magnetocaloric effect and notable magnetoresistance within the liquid nitrogen temperature range. At 100 K, the magnetoresistance reaches approximately 70% under an external magnetic field of 20 kOe. The magnetocaloric entropy change is calculated to be 3.5 J/kg-K for a 70 kOe magnetic field, with the entropy change curve exhibiting a broadened peak, leading to a substantial Relative Cooling Power (RCP). These findings enhance our understanding of the material’s behavior and highlight its potential for various technological applications.
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Journal articleHayrapetyan A, Tumasyan A, Adam W, et al., 2025,
Search for a standard model-like Higgs boson in the mass range between 70 and 110 GeV in the diphoton final state in proton-proton collisions at s=13TeV
, Physics Letters Section B Nuclear Elementary Particle and High Energy Physics, Vol: 860, ISSN: 0370-2693The results of a search for a standard model-like Higgs boson decaying into two photons in the mass range between 70 and 110 GeV are presented. The analysis uses the data set collected by the CMS experiment in proton-proton collisions at s=13TeV corresponding to integrated luminosities of 36.3fb<sup>−1</sup>, 41.5fb<sup>−1</sup> and 54.4fb<sup>−1</sup> during the 2016, 2017, and 2018 LHC running periods, respectively. No significant excess over the background expectation is observed and 95% confidence level upper limits are set on the product of the cross section and branching fraction for decays of an additional Higgs boson into two photons. The maximum deviation with respect to the background is seen for a mass hypothesis of 95.4 GeV with a local (global) significance of 2.9 (1.3) standard deviations. The observed upper limit ranges from 15 to 73 fb.
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Journal articleAaij R, Abdelmotteleb ASW, Abellan Beteta C, et al., 2024,
Measurement of Λ_{b}^{0}, Λ_{c}^{+}, and Λ Decay Parameters Using Λ_{b}^{0}→Λ_{c}^{+}h^{-} Decays.
, Phys Rev Lett, Vol: 133A comprehensive study of the angular distributions in the bottom-baryon decays Λ_{b}^{0}→Λ_{c}^{+}h^{-}(h=π,K), followed by Λ_{c}^{+}→Λh^{+} with Λ→pπ^{-} or Λ_{c}^{+}→pK_{S}^{0} decays, is performed using a data sample of proton-proton collisions corresponding to an integrated luminosity of 9 fb^{-1} collected by the LHCb experiment at center-of-mass energies of 7, 8, and 13 TeV. The decay parameters and the associated charge-parity (CP) asymmetries are measured, with no significant CP violation observed. For the first time, the Λ_{b}^{0}→Λ_{c}^{+}h^{-} decay parameters are measured. The most precise measurements of the decay parameters α, β, and γ are obtained for Λ_{c}^{+} decays and an independent measurement of the decay parameters for the strange-baryon Λ decay is provided. The results deepen our understanding of weak decay dynamics in baryon decays.
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Journal articlePal K, Dey S, Alam A, et al., 2024,
Revealing exchange bias in spin compensated systems for spintronics applications.
, Sci Rep, Vol: 14Antiferromagnetic materials offer potential for spintronic applications due to their resilience to magnetic field perturbations and lack of stray fields. Achieving exchange bias in these materials is crucial for certain applications; however, discovering such materials remains challenging due to their compensated spin structure. The quest for antiferromagnetic materials with exchange bias became a reality through our experimental study and theoretical simulation on Sr 2 FeIrO 6 and Sr 2 CoIrO 6 . This study also unveils the impact of ionic disorder and lattice distortion on magnetic properties. The presence of exchange bias in both materials, given their antiferromagnetic nature, is intriguing. This study opens up new avenues for achieving exchange bias in spin-compensated systems, offering potential for low power and ultra fast antiferromagnetic spintronic applications in future research endeavors.
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Journal articleChatterjee S, Das I, 2024,
Desertion of anomalous magnetic transition and emergence of metallic state in Cu doped Eu2Ru2O7 pyrochlore.
, J Chem Phys, Vol: 161In this paper, we present a detailed investigation of the structural, magnetic, and electrical transport properties of Eu2-xCuxRu2O7 (x = 0, 0.2, 0.4) pyrochlores. X-ray diffraction measurements confirm the single-phase nature of all samples and also manifest the reduction of lattice parameters with the increase in copper doping concentration. The experimental results of the magnetic measurements indicate that an anomalous magnetic transition around 23 K arises due to the contribution of non-magnetic Eu3+ ions. The strength of this unnatural magnetic transition reduces with decreasing Eu concentration [i.e., with increasing copper doping (x)] and finally disappears for x = 0.4. Moreover, electrical transport measurements reveal a considerable decrease in resistivity for Cu doped samples compared to undoped samples, which indicates the increase in charge carrier concentration with increasing Cu content.
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Journal articleHayrapetyan A, Tumasyan A, Adam W, et al., 2024,
Model-independent search for pair production of new bosons decaying into muons in proton-proton collisions at $$ \sqrt{s} $$ = 13 TeV
, Journal of High Energy Physics, Vol: 2024<jats:title>A<jats:sc>bstract</jats:sc> </jats:title> <jats:p>The results of a model-independent search for the pair production of new bosons within a mass range of 0<jats:italic>.</jats:italic>21 <jats:italic>< m <</jats:italic> 60 GeV, are presented. This study utilizes events with a four-muon final state. We use two data sets, comprising 41<jats:italic>.</jats:italic>5 fb<jats:sup> <jats:italic>−</jats:italic>1</jats:sup> and 59<jats:italic>.</jats:italic>7 fb<jats:sup> <jats:italic>−</jats:italic>1</jats:sup> of 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> = 13 TeV, recorded in 2017 and 2018 by the CMS experiment at the CERN LHC. The study of the 2018 data set includes a search for displaced signatures of a new boson within the proper decay length range of 0 <jats:italic>< cτ <</jats:italic> 100 mm. Our results are combined with a previous CMS result, based on 35<jats:italic>.</jats:italic>9 fb<jats:sup> <jats:italic>−</jats:italic>1</jats:sup> of 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>
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Journal articleAaij R, Abdelmotteleb ASW, Abellan Beteta C, et al., 2024,
Measurement of CP Violation Observables in D^{+}→K^{-}K^{+}π^{+} Decays.
, Phys Rev Lett, Vol: 133A search for violation of the charge-parity (CP) symmetry in the D^{+}→K^{-}K^{+}π^{+} decay is presented, with proton-proton collision data corresponding to an integrated luminosity of 5.4 fb^{-1}, collected at a center-of-mass energy of 13 TeV with the LHCb detector. A novel model-independent technique is used to compare the D^{+} and D^{-} phase-space distributions, with instrumental asymmetries subtracted using the D_{s}^{+}→K^{-}K^{+}π^{+} decay as a control channel. The p value for the hypothesis of CP conservation is 8.1%. The CP asymmetry observables A_{CP|S}^{ϕπ^{+}}=(0.95±0.43_{stat}±0.26_{syst})×10^{-3} and A_{CP|S}^{K[over ¯]^{*0}K^{+}}=(-0.26±0.56_{stat}±0.18_{syst})×10^{-3} are also measured. These results show no evidence of CP violation and represent the most sensitive search performed through the phase space of a multibody decay.
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Journal articleMazumdar D, Das K, Das I, 2024,
Magnetic exchange coupled composite behavior in the doped manganite nanoparticles: A proposed phenomenological model
, Physica B Condensed Matter, Vol: 695, ISSN: 0921-4526In this paper, we comprehensively investigate the isothermal magnetization behavior of doped perovskite manganite nanoparticles. The focus is on understanding the impact of variation of particle sizes on the soft and hard magnetic phases with respect to the changes in the coercive field and remanent magnetization, both theoretically and experimentally. The study seeks to correlate experimental findings with the proposed phenomenological model to gain deeper insights into the underlying mechanisms governing exchange coupling and anisotropy effects in the nanocrystalline composites. The proposed phenomenological model beautifully demonstrates how the values of saturation magnetization and coercive field changes with changing the particle size in the nanocrystalline La<inf>0.48</inf>Ca<inf>0.52</inf>MnO<inf>3</inf> (LCMO48) and La<inf>0.46</inf>Ca<inf>0.54</inf>MnO<inf>3</inf> (LCMO46) compounds. In addition, the model provide an insights into the limitations of critical radius, size and shape of the nanocrystalline particle. This investigation looks into how the size of particles affects their magnetic properties, specifically coercive field and remanent magnetization.
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Journal articleDas K, Mazumdar D, Das I, 2024,
Structural distortion driven polaronic transport and table-like magnetocaloric properties in polycrystalline Tb0.7Sr0.3MnO3 compound.
, Phys Chem Chem Phys, Vol: 26, Pages: 29987-30001This research mainly explores the structural, magnetic, magneto-transport, and magnetocaloric properties of the polycrystalline Tb0.7Sr0.3MnO3 compound. The results reveal a significant modification of the compound's ground state with increasing the strength of the magnetic field. The strong distortion in the crystal structure highly controls the magnetic and magneto-transport properties of the system. Along with this, a prominent 'table-like' nature in the temperature-dependent magnetic entropy change has been noticed, showcasing the potential application of the compound in the field of Ericsson refrigeration technology. Notably, a substantial low-field magnetoresistance is noticed around T ∼ 60 K. The temperature dependent electrical resistivity data can be well explained with the help of polaronic transport conduction mechanisms namely small-polaron hopping and variable-range hopping models. Various significant parameters are calculated and the system possesses a non-adiabatic polaron hopping mechanism with a large electron-phonon coupling constant. This investigation contributes valuable insights into the intricate dynamics of the 3d-4f exchange interaction and crystallographic distortion, shedding light on the underlying mechanisms governing the magnetic and electrical transport properties of the Sr-doped TbMnO3 compound.
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Journal articleHayrapetyan A, Tumasyan A, Adam W, et al., 2024,
Search for CP violation in $${{{\textrm{D}}}^{{0}}} \rightarrow {{\textrm{K}} _{\text {S}}^{{0}}} {{\textrm{K}} _{\text {S}}^{{0}}} $$ decays in proton–proton collisions at $$\sqrt{s} = 13\,\text {Te}\hspace{-.08em}\text {V} $$
, The European Physical Journal C, Vol: 84<jats:title>Abstract</jats:title> <jats:p>A search is reported for charge-parity <jats:inline-formula> <jats:alternatives> <jats:tex-math>$$CP$$</jats:tex-math> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:mi>CP</mml:mi> </mml:mrow> </mml:math> </jats:alternatives> </jats:inline-formula> violation in <jats:inline-formula> <jats:alternatives> <jats:tex-math>$${{{\textrm{D}}}^{{0}}} \rightarrow {{\textrm{K}} _{\text {S}}^{{0}}} {{\textrm{K}} _{\text {S}}^{{0}}} $$</jats:tex-math> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:msup> <mml:mrow> <mml:mtext>D</mml:mtext> </mml:mrow> <mml:mn>0</mml:mn> </mml:msup> <mml:mo>→</mml:mo> <mml:msubsup> <mml:mtext>K</mml:mtext> <mml:mrow> <mml:mtext>S</mml:mtext> </mml:mrow> <mml:mn>0</mml:mn> </mml:msubsup> <mml:msubsup> <mml:mtext>K</mml:mtext> <mml:mrow> <mml:mtext>S</mml:mtext> </mml:mrow> <mml:mn>0</mml:mn> </mml:msubsup> </mml:mrow> </mml:math> </jats:alternati
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Journal articleHayrapetyan A, Tumasyan A, Adam W, et al., 2024,
Measurements of polarization and spin correlation and observation of entanglement in top quark pairs using (Formula presented) events from proton-proton collisions at (Formula presented)
, Physical Review D, Vol: 110, ISSN: 2470-0010Measurements of the polarization and spin correlation in top quark pairs ((Formula presented)) are presented using events with a single electron or muon and jets in the final state. The measurements are based on proton-proton collision data from the LHC at (Formula presented) collected by the CMS experiment, corresponding to an integrated luminosity of (Formula presented). All coefficients of the polarization vectors and the spin correlation matrix are extracted simultaneously by performing a binned likelihood fit to the data. The measurement is performed inclusively and in bins of additional observables, such as the mass of the (Formula presented) system and the top quark scattering angle in the (Formula presented) rest frame. The measured polarization and spin correlation are in agreement with the standard model. From the measured spin correlation, conclusions on the (Formula presented) spin entanglement are drawn by applying the Peres-Horodecki criterion. The standard model predicts entangled spins for (Formula presented) states at the production threshold and at high masses of the (Formula presented) system. Entanglement is observed for the first time in events at high (Formula presented) mass, where a large fraction of the (Formula presented) decays are spacelike separated, with an expected and observed significance of above 5 standard deviations.
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Journal articleHayrapetyan A, Tumasyan A, Adam W, et al., 2024,
Measurement of boosted Higgs bosons produced via vector boson fusion or gluon fusion in the H →bb¯ decay mode using LHC proton-proton collision data at s = 13 TeV
, Journal of High Energy Physics, Vol: 2024A measurement is performed of Higgs bosons produced with high transverse momentum (p<inf>T</inf>) via vector boson or gluon fusion in proton-proton collisions. The result is based on a data set with a center-of-mass energy of 13 TeV collected in 2016–2018 with the CMS detector at the LHC and corresponds to an integrated luminosity of 138 fb<sup>−1</sup>. The decay of a high-p<inf>T</inf> Higgs boson to a boosted bottom quark-antiquark pair is selected using large-radius jets and employing jet substructure and heavy-flavor taggers based on machine learning techniques. Independent regions targeting the vector boson and gluon fusion mechanisms are defined based on the topology of two quark-initiated jets with large pseudorapidity separation. The signal strengths for both processes are extracted simultaneously by performing a maximum likelihood fit to data in the large-radius jet mass distribution. The observed signal strengths relative to the standard model expectation are 4.9−1.6+1.9 and 1.6−1.5+1.7 for the vector boson and gluon fusion mechanisms, respectively. A differential cross section measurement is also reported in the simplified template cross section framework.
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Journal articleAbbaneo D, Ahmad S, Albanese R, et al., 2024,
An integrated flux-symmetric spectrometer-magnet system for the SND@LHC experiment upgrade
, Journal of Instrumentation, Vol: 19The proposed upgrade of the SND@LHC experiment for the High Luminosity phase of the LHC (HL-LHC) will strongly benefit from the presence of a magnetized region, allowing for muon momentum and charge measurement. In this paper we describe an iron core magnet system that is partly integrated with the calorimeter and that is designed to respect the strict constraints from the available space in the experimental cavern, power consumption, and field requirements. Semi-analytical tools are introduced to explore the parameter space, in order to define the primary design options. A full 3-D analysis is then performed in order to validate the optimal choice, and to propose a conceptual design, including sizing of the components, detector performances and stray fields. Several technical options are also discussed, anticipating the design phase.
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Journal articleAbed Abud A, Abi B, Acciarri R, et al., 2024,
DUNE Phase II: scientific opportunities, detector concepts, technological solutions
, Journal of Instrumentation, Vol: 19The international collaboration designing and constructing the Deep Underground Neutrino Experiment (DUNE) at the Long-Baseline Neutrino Facility (LBNF) has developed a two-phase strategy toward the implementation of this leading-edge, large-scale science project. The 2023 report of the US Particle Physics Project Prioritization Panel (P5) reaffirmed this vision and strongly endorsed DUNE Phase I and Phase II, as did the European Strategy for Particle Physics. While the construction of the DUNE Phase I is well underway, this White Paper focuses on DUNE Phase II planning. DUNE Phase-II consists of a third and fourth far detector (FD) module, an upgraded near detector complex, and an enhanced 2.1 MW beam. The fourth FD module is conceived as a "Module of Opportunity", aimed at expanding the physics opportunities, in addition to supporting the core DUNE science program, with more advanced technologies. This document highlights the increased science opportunities offered by the DUNE Phase II near and far detectors, including long-baseline neutrino oscillation physics, neutrino astrophysics, and physics beyond the standard model. It describes the DUNE Phase II near and far detector technologies and detector design concepts that are currently under consideration. A summary of key R & D goals and prototyping phases needed to realize the Phase II detector technical designs is also provided. DUNE's Phase II detectors, along with the increased beam power, will complete the full scope of DUNE, enabling a multi-decadal program of groundbreaking science with neutrinos.
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Journal articleAaij R, Abdelmotteleb ASW, Abellan Beteta C, et al., 2024,
Analysis of Λ0b→ pK−μ+μ− decays
, Journal of High Energy Physics, Vol: 2024The differential branching fraction and angular coefficients of Formula Presented decays are measured in bins of the dimuon mass squared and dihadron mass. The analysis is performed using a data set corresponding to 9 fb−1 of integrated luminosity collected with the LHCb detector between 2011 and 2018. The data are consistent with receiving contributions from a mixture of Λ resonances with different spin-parity quantum numbers. The angular coefficients show a pattern of vector-axial vector interference that is a characteristic of the type of flavour-changing neutral-current transition relevant for these decays.
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