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Taliercio, A. (ORCID:0000000251196280)

Publications and source records attributed to Taliercio, A. (ORCID:0000000251196280).

43 records · Page 3
All sourcesNASA NTRSDOE OSTI
DOE OSTI2023

Search for nonresonant Higgs boson pair production in final state with two bottom quarks and two tau leptons in proton-proton collisions at $\sqrt{s}$ = 13 TeV

A search for the nonresonant production of Higgs boson pairs (HH ) via gluon-gluon and vector boson fusion processes in final states with two bottom quarks and two tau leptons is presented. The search uses data from proton-proton collisions at a center-of-mass energy of $\sqrt{s}$ = 13 TeV recorded with the CMS detector at the LHC, corresponding to an integrated luminosity of 138 fb -1 . Events in which at least one tau lepton decays hadronically are considered and multiple machine learning techniques are used to identify and extract the signal. The data are found to be consistent, within uncertainties, with the standard model (SM) predictions. Upper limits on the HH production cross section are set to constrain the parameter space for anomalous Higgs boson couplings. The observed (expected) upper limit at 95% confidence level corresponds to 3.3 (5.2) times the SM prediction for the inclusive HH cross section and to 124 (154) times the SM prediction for the vector boson fusion HH cross section. At 95% confidence level, the Higgs field self-coupling is constrained to be within -1.7 and 8.7 times the SM expectation, and the coupling of two Higgs bosons to two vector bosons is constrained to be within -0.4 and 2.6 times the SM expectation.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2023

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

Decays of the Higgs boson into a z boson and a J/ψ or ψ(2S) meson are searched for in four-lepton final states with the CMS detector at the LHC. A data set of proton-proton collisions corresponding to an integrated luminosity of 138 fb -1 is used. Using the same data set, decays of the Higgs and z boson into quarkonium pairs are also searched for. An observation of such decays with this sample would indicate the presence of physics beyond the standard model. No evidence for these decays has been observed and upper limits at the 95% confidence level are placed on the corresponding branching fractions ($\mathscr{B}$). Assuming longitudinal polarization of the Higgs boson decay products, 95% confidence level observed upper limits for $\mathcal{B}$(H→ZJ/ψ) and $\mathcal{B}$(H→Zψ(2S)) are 1.9 X 10 -3 and 6.6 X 10 -3 , respectively.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2023

Search for electroweak production of charginos and neutralinos at $\sqrt{s}$ = 13 TeV in final states containing hadronic decays of WW, WZ, or WH and missing transverse momentum

This Letter presents a search for direct production of charginos and neutralinos via electroweak interactions. The results are based on data from proton-proton collisions at a center-of-mass energy of 13 TeV collected with the CMS detector at the LHC, corresponding to an integrated luminosity of 137 fb -1 . The search considers final states with large missing transverse momentum and pairs of hadronically decaying bosons WW, WZ, and WH, where H is the Higgs boson. These bosons are identified using novel algorithms. No significant excess of events is observed relative to the expectations from the standard model. Limits at the 95% confidence level are placed on the cross section for production of mass-degenerate wino-like supersymmetric particles $\widetilde{χ}_1^±$ and $\widetilde{χ}_2^0$, and mass-degenerate higgsino-like supersymmetric particles $\widetilde{χ}_1^±$, $\widetilde{χ}_2^0$, and $\widetilde{χ}_3^0$. In the limit of a nearly-massless lightest supersymmetric particle $\widetilde{χ}_1^0$, wino-like particles with masses up to 870 and 960 GeV are excluded in the cases of $\widetilde{χ}_2^0$→Z$\widetilde{χ}_1^0$ and $\widetilde{χ}_2^0$→$\widetilde{χ}_1^0$, respectively, and higgsino-like particles are excluded between 300 and 650 GeV.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2023

Measurement of the $B_s^0$ → μ + μ - decay properties and search for the B 0 → μ + μ - decay in proton-proton collisions at $\sqrt{s}$ = 13 TeV

Measurements are presented of the $B_s^0$ → μ + μ - branching fraction and effective lifetime, as well as results of a search for the B 0 → μ + μ - decay in proton-proton collisions at at the LHC. The analysis is based on data collected with the CMS detector in 2016–2018 corresponding to an integrated luminosity of 140 fb -1 . The branching fraction of the $B_s^0$ → μ + μ - decay and the effective $B_s^0$ meson lifetime are the most precise single measurements to date. No evidence for the B 0 → μ + μ - decay has been found. All results are found to be consistent with the standard model predictions and previous measurements.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2023

Observation of electroweak W + W – pair production in association with two jets in proton-proton collisions at √s = 13 TeV

An observation is reported of the electroweak production of a W + W – pair in association with two jets, with both W bosons decaying leptonically. The data sample corresponds to an integrated luminosity of 138 fb –1 of proton-proton collisions at √s = 13 TeV, collected by the CMS detector at the CERN LHC. Events are selected by requiring exactly two opposite-sign leptons (electrons or muons) and two jets with large pseudorapidity separation and high dijet invariant mass. Events are categorized based on the flavor of the final-state leptons. A signal is observed with a significance of 5.6 standard deviations (5.2 expected) with respect to the background-only hypothesis. The measured fiducial cross section is 10.2 ± 2.0 fb and this value is consistent with the standard model prediction of 9.1 ± 0.6 fb.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2022

Search for a massive scalar resonance decaying to a light scalar and a Higgs boson in the four b quarks final state with boosted topology

We search for new massive scalar particles X and Y through the resonant process X→YH→$b\bar{b}b\bar{b}$, where H is the standard model Higgs boson. Data from CERN LHC proton-proton collisions are used, collected at a centre-of-mass energy of 13 TeV in 2016–2018 and corresponding to an integrated luminosity of 138 fb -1 . The search is performed in mass ranges of 0.9–4 TeV for X and 60–600 GeV for Y, where both Y and H are reconstructed as Lorentz-boosted single large-area jets. The results are interpreted in the context of the next-to-minimal supersymmetric standard model and also in an extension of the standard model with two additional singlet scalar fields. The 95% confidence level upper limits for the production cross section vary between 0.1 and 150 fb depending on the X and Y masses, and represent a significant improvement over results from previous searches.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2022

A portrait of the Higgs boson by the CMS experiment ten years after the discovery

In July 2012, the ATLAS and CMS collaborations at the CERN Large Hadron Collider announced the observation of a Higgs boson at a mass of around 125 gigaelectronvolts. Ten years later, and with the data corresponding to the production of a 30-times larger number of Higgs bosons, we have learnt much more about the properties of the Higgs boson. The CMS experiment has observed the Higgs boson in numerous fermionic and bosonic decay channels, established its spin–parity quantum numbers, determined its mass and measured its production cross-sections in various modes. Here the CMS Collaboration reports the most up-to-date combination of results on the properties of the Higgs boson, including the most stringent limit on the cross-section for the production of a pair of Higgs bosons, on the basis of data from proton–proton collisions at a centre-of-mass energy of 13 teraelectronvolts. Within the uncertainties, all these observations are compatible with the predictions of the standard model of elementary particle physics. Much evidence points to the fact that the standard model is a low-energy approximation of a more comprehensive theory. Several of the standard model issues originate in the sector of Higgs boson physics. An order of magnitude larger number of Higgs bosons, expected to be examined over the next 15 years, will help deepen our understanding of this crucial sector.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗