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Journal articleAcar B, Adamov G, Adloff C, et al., 2023,
Neutron irradiation and electrical characterisation of the first 8" silicon pad sensor prototypes for the CMS calorimeter endcap upgrade
, Journal of Instrumentation, Vol: 18As part of its HL-LHC upgrade program, the CMS collaboration is replacing its existing endcap calorimeters with a high-granularity calorimeter (CE). The new calorimeter is a sampling calorimeter with unprecedented transverse and longitudinal readout for both electromagnetic and hadronic compartments. Due to its compactness, intrinsic time resolution, and radiation hardness, silicon has been chosen as active material for the regions exposed to higher radiation levels. The silicon sensors are fabricated as 20 cm (8") wide hexagonal wafers and are segmented into several hundred pads which are read out individually. As part of the sensor qualification strategy, 8"sensor irradiation with neutrons has been conducted at the Rhode Island Nuclear Science Center (RINSC) and followed by their electrical characterisation in 2020-21. The completion of this important milestone in the CE's R&D program is documented in this paper and it provides detailed account of the associated infrastructure and procedures. The results on the electrical properties of the irradiated CE silicon sensors are presented.
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Journal articleAaij R, Abdelmotteleb ASW, Abellan Beteta C, et al., 2023,
Measurement of lepton universality parameters in B+ →k+ℓ+ℓ- and B0 →k∗0ℓ+ℓ- decays
, Physical Review D, Vol: 108, ISSN: 2470-0010A simultaneous analysis of the B+→K+ℓ+ℓ- and B0→K∗0ℓ+ℓ- decays is performed to test muon-electron universality in two ranges of the square of the dilepton invariant mass, q2. The measurement uses a sample of beauty meson decays produced in proton-proton collisions collected with the LHCb detector between 2011 and 2018, corresponding to an integrated luminosity of 9 fb-1. A sequence of multivariate selections and strict particle identification requirements produce a higher signal purity and a better statistical sensitivity per unit luminosity than previous LHCb lepton universality tests using the same decay modes. Residual backgrounds due to misidentified hadronic decays are studied using data and included in the fit model. Each of the four lepton universality measurements reported is either the first in the given q2 interval or supersedes previous LHCb measurements. The results are compatible with the predictions of the Standard Model.
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Journal articleAaij R, Abdelmotteleb ASW, Abellan Beteta C, et al., 2023,
First observation of the B+ → Ds+ Ds- K+ decay
, Physical Review D, Vol: 108, ISSN: 2470-0010The B+→Ds+Ds-K+ decay is observed for the first time using proton-proton collision data collected by the LHCb detector at center-of-mass energies of 7, 8, and 13 TeV, corresponding to an integrated luminosity of 9 fb-1. Its branching fraction relative to that of the B+→D+D-K+ decay is measured to be B(B+→Ds+Ds-K+)B(B+→D+D-K+)=0.525±0.033±0.027±0.034, where the first uncertainty is statistical, the second systematic, and the third is due to the uncertainties on the branching fractions of the Ds±→K∓K±π± and D±→K∓π±π± decays. This measurement fills an experimental gap in the knowledge of the family of Cabibbo-favored b¯→c¯cs¯ transitions and opens the path for unique studies of spectroscopy in future.
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Journal articleTumasyan A, Adam W, Andrejkovic JW, et al., 2023,
Search for high-mass exclusive γγ → WW and γγ → ZZ production in proton-proton collisions at $$ \sqrt{s} $$ = 13 TeV
, Journal of High Energy Physics, Vol: 2023<jats:title>A<jats:sc>bstract</jats:sc> </jats:title><jats:p>A search is performed for exclusive high-mass <jats:italic>γγ</jats:italic> → WW and <jats:italic>γγ</jats:italic> → ZZ production in proton-proton collisions using intact forward protons reconstructed in near-beam detectors, with both weak bosons decaying into boosted and merged jets. The analysis is based on a sample of proton-proton collisions collected by the CMS and TOTEM experiments 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, corresponding to an integrated luminosity of 100 fb<jats:sup><jats:italic>−</jats:italic>1</jats:sup>. No excess above the standard model background prediction is observed, and upper limits are set on the pp → pWWp and pp → pZZp cross sections in a fiducial region defined by the diboson invariant mass <jats:italic>m</jats:italic>(VV) <jats:italic>></jats:italic> 1 TeV (with V = W<jats:italic>,</jats:italic> Z) and proton fractional momentum loss 0<jats:italic>.</jats:italic>04 <jats:italic>< ξ <</jats:italic> 0<jats:italic>.</jats:italic>20. The results are interpreted as new limits on dimension-6 and dimension-8 anomalous quartic gauge couplings.</jats:p>
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Journal articleKotlorz D, Christova E, Leader E, 2023,
Tests of the parametrizations of fragmentation functions using data on inclusive pion and kaon production in unpolarized pp collisions from the STAR collaboration and at the NICA project
, International Journal of Modern Physics A, Vol: 38, ISSN: 0217-751XThe goal of this study is to check which, if any, of the published versions of the pion and kaon fragmentation functions (FFs) is compatible with the STAR data on semi-inclusive pion and kaon production in proton{proton collisions, and on the basis of this analysis to make reliable predictions for the pT spectra of the pions and kaons in inclusive pion and kaon production at the future NICA proton{proton collider. The calculations are carried out in next-to-leading order (NLO) of perturbative quantum chromodynamics (pQCD), using the well-tested CTEQ6 parton distributions. We consider the following pion and kaon FFs DSEHS-14 [D. de Florian, R. Sassot, M. Epele, R. J. Hern andez-Pinto and M. Stratmann, Phys. Rev. D 91, 014035 (2015), 1410.6027], DSEHS-17 [D. de Florian, M. Epele, R. J. Hernandez-Pinto, R. Sassot and M. Stratmann, Phys. Rev. D 95, 094019 (2017), 1702.06353], LSS-15 [E. Leader, A. V. Sidorov and D. B. Stamenov, Phys. Rev. D 93, 074026 (2016), 1506.06381], HKNS-07 [M. Hirai, S. Kumano, T. H. Nagai and K. Sudoh, Phys. Rev. D 75, 094009 (2007), hep-ph/0702250] and AKK-08 [S. Albino, B. A. Kniehl and G. Kramer, Nucl. Phys. B 803, 42 (2008), 0803.2768]. Our analysis shows that within the experimental errors all tested sets of FFs provide a good fit to STAR data at the c.m. energy [Formula presented], and the best ones are both LSS-15 and DSEHS-14 for pions and DSEHS-17 for kaons. From comparison of the LO and NLO results it is clear that the latter fit data much better, specially in the region of small pT. The NLO cross-sections are also less scale-Q2 dependent, where pT =2 Q 2pT, than the LO ones. In order to make predictions for NICA energies, we compare the NLO pQCD results with the existing experimental BES STAR data on semi-inclusive hadron production in the most peripheral Au +Au collisions where the nuclear effects can be neglected. The comparison for lower energy scales, like at NICA, shows that a purely pQCD approach is inadequate and suggests the n
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Journal articleAaij R, Abdelmotteleb ASW, Abellan Beteta C, et al., 2023,
Search for Rare Decays of D^{0} Mesons into Two Muons.
, Phys Rev Lett, Vol: 131A search for the very rare D^{0}→μ^{+}μ^{-} decay is performed using data collected by the LHCb experiment in proton-proton collisions at sqrt[s]=7, 8, and 13 TeV, corresponding to an integrated luminosity of 9 fb^{-1}. The search is optimized for D^{0} mesons from D^{*+}→D^{0}π^{+} decays but is also sensitive to D^{0} mesons from other sources. No evidence for an excess of events over the expected background is observed. An upper limit on the branching fraction of this decay is set at B(D^{0}→μ^{+}μ^{-})<3.1×10^{-9} at a 90% C.L. This represents the world's most stringent limit, constraining models of physics beyond the standard model.
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Journal articleAaij R, Abdelmotteleb ASW, Abellan Beteta C, et al., 2023,
Nuclear Modification Factor of Neutral Pions in the Forward and Backward Regions in p-Pb Collisions.
, Phys Rev Lett, Vol: 131The nuclear modification factor of neutral pions is measured in proton-lead collisions collected at a center-of-mass energy per nucleon of 8.16 TeV with the LHCb detector. The π^{0} production cross section is measured differentially in transverse momentum (p_{T}) for 1.5<p_{T}<10.0 GeV and in center-of-mass pseudorapidity (η_{c.m.}) regions 2.5<η_{c.m.}<3.5 (forward) and -4.0<η_{c.m.}<-3.0 (backward) defined relative to the proton beam direction. The forward measurement shows a sizable suppression of π^{0} production, while the backward measurement shows the first evidence of π^{0} enhancement in proton-lead collisions at the LHC. Together, these measurements provide precise constraints on models of nuclear structure and particle production in high-energy nuclear collisions.
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Journal articleAalbers J, Akerib DS, Akerlof CW, et al., 2023,
First Dark Matter Search Results from the LUX-ZEPLIN (LZ) Experiment
, PHYSICAL REVIEW LETTERS, Vol: 131, ISSN: 0031-9007- Author Web Link
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- Citations: 5
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Journal articleAaij R, Abdelmotteleb ASW, Beteta CA, et al., 2023,
Amplitude analysis of the ?<sub>c</sub><SUP>+</SUP>- pK-p<SUP>+</SUP> decay and ?<sub>c</sub><SUP>+</SUP> baryon polarization measurement in semileptonic beauty hadron decays
, PHYSICAL REVIEW D, Vol: 108, ISSN: 2470-0010 -
Journal articleTumasyan A, Adam W, Andrejkovic JW, et al., 2023,
Measurement of the cross section of top quark-antiquark pair production in association with a W boson in proton-proton collisions at √s=13 TeV
, JOURNAL OF HIGH ENERGY PHYSICS, ISSN: 1029-8479 -
Journal articleAaij R, Abdelmotteleb ASW, Beteta CA, et al., 2023,
Search for the baryon- and lepton-number violating decays <i>B</i><SUP>0</SUP> → <i>p</i>μ<SUP>-</SUP> and <i>B<sub>s</sub></i><SUP>0</SUP> → <i>p</i>μ<SUP>-</SUP>
, PHYSICAL REVIEW D, Vol: 108, ISSN: 2470-0010 -
Journal articleTumasyan A, Adam W, Andrejkovic JW, et al., 2023,
Search for Nonresonant Pair Production of Highly Energetic Higgs Bosons Decaying to Bottom Quarks.
, Phys Rev Lett, Vol: 131A search for nonresonant Higgs boson (H) pair production via gluon and vector boson (V) fusion is performed in the four-bottom-quark final state, using proton-proton collision data at 13 TeV corresponding to 138 fb^{-1} collected by the CMS experiment at the LHC. The analysis targets Lorentz-boosted H pairs identified using a graph neural network. It constrains the strengths relative to the standard model of the H self-coupling and the quartic VVHH couplings, κ_{2V}, excluding κ_{2V}=0 for the first time, with a significance of 6.3 standard deviations when other H couplings are fixed to their standard model values.
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Journal articleTumasyan A, Adam W, Andrejkovic JW, et al., 2023,
Search for Higgs Boson and Observation of Z Boson through Their Decay into a Charm Quark-Antiquark Pair in Boosted Topologies in Proton-Proton Collisions at sqrt[s]=13 TeV.
, Phys Rev Lett, Vol: 131A search for the standard model (SM) Higgs boson (H) produced with transverse momentum (p_{T}) greater than 450 GeV and decaying to a charm quark-antiquark (cc[over ¯]) pair is presented. The search is performed using proton-proton collision data collected at sqrt[s]=13 TeV by the CMS experiment at the LHC, corresponding to an integrated luminosity of 138 fb^{-1}. Boosted H→cc[over ¯] decay products are reconstructed as a single large-radius jet and identified using a deep neural network charm tagging technique. The method is validated by measuring the Z→cc[over ¯] decay process, which is observed in association with jets at high p_{T} for the first time with a signal strength of 1.00_{-0.14}^{+0.17}(syst)±0.08(theo)±0.06(stat), defined as the ratio of the observed process rate to the SM expectation. The observed (expected) upper limit on σ(H)B(H→cc[over ¯]) is set at 47 (39) times the SM prediction at 95% confidence level.
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Journal articleTumasyan A, Adam W, Andrejkovic JW, et al., 2023,
Search for long-lived particles using out-of-time trackless jets in proton-proton collisions at √<i>s</i>=13 TeV
, JOURNAL OF HIGH ENERGY PHYSICS, ISSN: 1029-8479 -
Journal articleAaij R, Abdelmotteleb ASW, Beteta CA, et al., 2023,
First Observation of a Doubly Charged Tetraquark and Its Neutral Partner
, PHYSICAL REVIEW LETTERS, Vol: 131, ISSN: 0031-9007- Author Web Link
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- Citations: 1
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Journal articleAaij R, Abdelmotteleb ASW, Beteta CA, et al., 2023,
Search for $$D^{*}(2007)^{0} \rightarrow \mu ^{+} \mu ^{-}$$ in $$B^{-}\rightarrow \pi ^{-} \mu ^{+} \mu ^{-}$$ decays
, The European Physical Journal C, Vol: 83<jats:title>Abstract</jats:title><jats:p>The very rare <jats:inline-formula><jats:alternatives><jats:tex-math>$${{D} ^*} (2007)^0\!\rightarrow {\mu ^+\mu ^-} $$</jats:tex-math><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:msup> <mml:mrow> <mml:mi>D</mml:mi> </mml:mrow> <mml:mo>∗</mml:mo> </mml:msup> <mml:msup> <mml:mrow> <mml:mo>(</mml:mo> <mml:mn>2007</mml:mn> <mml:mo>)</mml:mo> </mml:mrow> <mml:mn>0</mml:mn> </mml:msup> <mml:mspace /> <mml:mo>→</mml:mo> <mml:mrow> <mml:msup> <mml:mi>μ</mml:mi> <mml:mo>+</mml:mo> </mml:msup> <mml:msup> <mml:mi>μ</mml:mi> <mml:mo>-</mml:mo> </mml:msup> </mml:mrow> </mml:mrow> </mml:math></jats:alternatives></jats:inline-formula> decay is searched for by analysing <jats:inline-formula><jats:alternatives><jats:tex-math>$${{{B} ^-}} \!\rightarrow {{\pi } ^-} {\mu ^+\mu ^-} $$</jats:tex-math><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:msup> <mml:mrow>
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Journal articleAaij R, Abdelmotteleb ASW, Abellan Beteta C, et al., 2023,
Observation of a J/ψΛ Resonance Consistent with a Strange Pentaquark Candidate in B^{-}→J/ψΛp[over ¯] Decays.
, Phys Rev Lett, Vol: 131An amplitude analysis of B^{-}→J/ψΛp[over ¯] decays is performed using 4400 signal candidates selected on a data sample of pp collisions recorded at center-of-mass energies of 7, 8, and 13 TeV with the LHCb detector, corresponding to an integrated luminosity of 9 fb^{-1}. A narrow resonance in the J/ψΛ system, consistent with a pentaquark candidate with strangeness, is observed with high significance. The mass and the width of this new state are measured to be 4338.2±0.7±0.4 MeV and 7.0±1.2±1.3 MeV, where the first uncertainty is statistical and the second systematic. The spin is determined to be 1/2 and negative parity is preferred. Because of the small Q-value of the reaction, the most precise single measurement of the B^{-} mass to date, 5279.44±0.05±0.07 MeV, is obtained.
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Journal articleTumasyan A, Adam W, Andrejkovic JW, et al., 2023,
Search for resonant and nonresonant production of pairs of dijet resonances in proton-proton collisions at √s=13 TeV
, JOURNAL OF HIGH ENERGY PHYSICS, ISSN: 1029-8479 -
Journal articleAlbanese R, Alexandrov A, Alicante F, et al., 2023,
Observation of Collider Muon Neutrinos with the SND@LHC Experiment
, PHYSICAL REVIEW LETTERS, Vol: 131, ISSN: 0031-9007 -
Journal articleTumasyan A, Adam W, Andrejkovic JW, et al., 2023,
Search for the exotic decay of the Higgs boson into two light pseudoscalars with four photons in the final state in proton-proton collisions at $$ \sqrt{s} $$ = 13 TeV
, Journal of High Energy Physics, Vol: 2023<jats:title>A<jats:sc>bstract</jats:sc> </jats:title><jats:p>A search for the exotic decay of the Higgs boson to a pair of light pseudoscalars, each of which subsequently decays into a pair of photons, is presented. The search uses data from 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 with the CMS detector at the LHC that corresponds to an integrated luminosity of 132 fb<jats:sup><jats:italic>−</jats:italic>1</jats:sup>. The analysis probes pseudoscalar bosons with masses in the range 15–62 GeV, coming from the Higgs boson decay, which leads to four well-isolated photons in the final state. No significant deviation from the background-only hypothesis is observed. Upper limits are set on the product of the Higgs boson production cross section and branching fraction into four photons. The observed (expected) limits range from 0.80 (1.00) fb for a pseudoscalar boson mass of 15 GeV to 0.26 (0.24) fb for a mass of 62 GeV at 95% confidence level.</jats:p>
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Journal articleAalbers J, Akerib DS, Al Musalhi AK, et al., 2023,
Background determination for the LUX-ZEPLIN dark matter experiment
, PHYSICAL REVIEW D, Vol: 108, ISSN: 2470-0010 -
Journal articleTumasyan A, Adam W, Andrejkovic JW, et al., 2023,
Azimuthal anisotropy of dijet events in PbPb collisions at √<i>s</i><sub>NN</sub>=5.02 TeV
, JOURNAL OF HIGH ENERGY PHYSICS, ISSN: 1029-8479 -
Journal articleAbud AA, Abi B, Acciarri R, et al., 2023,
Reconstruction of interactions in the ProtoDUNE-SP detector with Pandora
, EUROPEAN PHYSICAL JOURNAL C, Vol: 83, ISSN: 1434-6044 -
Journal articleTumasyan A, Adam W, Andrejkovic JW, et al., 2023,
Search for top squark pair production in a final state with at least one hadronically decaying tau lepton in proton-proton collisions at $$ \sqrt{s} $$ = 13 TeV
, Journal of High Energy Physics, Vol: 2023<jats:title>A<jats:sc>bstract</jats:sc> </jats:title><jats:p>A search for pair production of the supersymmetric partner of the top quark, the top squark, in proton-proton collisions at <jats:inline-formula><jats:alternatives><jats:tex-math>$$ \sqrt{s} $$</jats:tex-math><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msqrt> <mml:mi>s</mml:mi> </mml:msqrt> </mml:math></jats:alternatives></jats:inline-formula> = 13 TeV is presented in final states containing at least one hadronically decaying tau lepton and large missing transverse momentum. This final state is highly sensitive to scenarios of supersymmetry in which the decay of the top squark to tau leptons is enhanced. The search uses a data sample corresponding to an integrated luminosity of 138 fb<jats:sup><jats:italic>−</jats:italic>1</jats:sup>, which was recorded with the CMS detector during 2016–2018. No significant excess is observed with respect to the standard model predictions. Exclusion limits at 95% confidence level on the masses of the top squark and the lightest neutralino are presented under the assumptions of simplified models. The results probe top squark masses up to 1150 GeV for a nearly massless neutralino. This search covers a relatively less explored parameter space in the context of supersymmetry, and the exclusion limit is the most stringent to date for the model considered here.</jats:p>
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Journal articleTumasyan A, Adam W, Andrejkovic JW, et al., 2023,
Search for Higgs boson pairs decaying to WW*WW*, WW*ττ, and ττττ in proton-proton collisions at $$ \sqrt{s} $$ = 13 TeV
, Journal of High Energy Physics, Vol: 2023<jats:title>A<jats:sc>bstract</jats:sc> </jats:title><jats:p>The results of a search for Higgs boson pair (HH) production in the WW<jats:sup>*</jats:sup>WW<jats:sup>*</jats:sup>, WW<jats:sup>*</jats:sup><jats:italic>ττ</jats:italic>, and <jats:italic>ττττ</jats:italic> decay modes are presented. The search uses 138 fb<jats:sup><jats:italic>−</jats:italic>1</jats:sup> of proton-proton collision data recorded by the CMS experiment at the LHC at a center-of-mass energy of 13 TeV from 2016 to 2018. Analyzed events contain two, three, or four reconstructed leptons, including electrons, muons, and hadronically decaying tau leptons. No evidence for a signal is found in the data. Upper limits are set on the cross section for nonresonant HH production, as well as resonant production in which a new heavy particle decays to a pair of Higgs bosons. For nonresonant production, the observed (expected) upper limit on the cross section at 95% confidence level (CL) is 21.3 (19.4) times the standard model (SM) prediction. The observed (expected) ratio of the trilinear Higgs boson self-coupling to its value in the SM is constrained to be within the interval −6<jats:italic>.</jats:italic>9 to 11.1 (−6<jats:italic>.</jats:italic>9 to 11.7) at 95% CL, and limits are set on a variety of new-physics models using an effective field theory approach. The observed (expected) limits on the cross section for resonant HH production range from 0.18 to 0.90 (0.08 to 1.06) pb at 95% CL for new heavy-particle masses in the range 250–1000 GeV.</jats:p>
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Journal articleTumasyan A, Adam W, Andrejkovic JW, et al., 2023,
Measurement of the Higgs boson inclusive and differential fiducial production cross sections in the diphoton decay channel with pp collisions at √s=13 TeV
, JOURNAL OF HIGH ENERGY PHYSICS, ISSN: 1029-8479 -
Journal articleTumasyan A, Adam W, Andrejkovic JW, et al., 2023,
Search for Higgs boson decays into Z and J/ψ and for Higgs and Z boson decays into J/ψ or Y pairs in pp collisions at √s=13 TeV
, PHYSICS LETTERS B, Vol: 842, ISSN: 0370-2693 -
Journal articleTumasyan A, Adam W, Andrejkovic JW, et al., 2023,
Measurement of the B<sub>s</sub><SUP>0</SUP> = μ<SUP>+</SUP>μ<SUP>-</SUP> decay properties and search for the B<SUP>0</SUP> → μ<SUP>+</SUP>μ<SUP>-</SUP> decay in proton-proton collisions at √<i>s</i>=13 TeV
, PHYSICS LETTERS B, Vol: 842, ISSN: 0370-2693 -
Journal articleTumasyan A, Adam W, Andrejkovic JW, et al., 2023,
Precision measurement of the Z boson invisible width in pp collisions √s=13 TeV
, PHYSICS LETTERS B, Vol: 842, ISSN: 0370-2693 -
Journal articleTumasyan A, Adam W, Andrejkovic JW, et al., 2023,
Search for electroweak production of charginos and neutralinos at √<i>s</i>=13 Tev in final states containing hadronic decays of WW, WZ, or WH and missing transverse momentum
, PHYSICS LETTERS B, Vol: 842, ISSN: 0370-2693
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