5,382 research outputs found
Mr P I A Karim, Professor S Chauduri, Professor S B H Abidi, and Professor A H Johns at a conference on the Qur'an
No full textMr P. I. A. Karim, (reader in education, University of Kerala, India); Professor S. Chauduri (Department of Islamic Hisotry and Culture, University of Calcutta); Professor S. B. H. Abidi (Department of Arabic, Hindu University of Benares); and Professor A. H. Johns (Conference Chairman, Department of Indonesian languages and literatures, Australian National University
Search for a light charged Higgs boson in t → H±b decays, with H± → cb, in the lepton+jets final state in proton-proton collisions at s = 13 TeV with the ATLAS detector
No full textA search for a charged Higgs boson, H±, produced in top-quark decays, t → H±b, is presented. The search targets H± decays into a bottom and a charm quark, H± → cb. The analysis focuses on a selection enriched in top-quark pair production, where one top quark decays into a leptonically decaying W boson and a bottom quark, and the other top quark decays into a charged Higgs boson and a bottom quark. This topology leads to a lepton-plus-jets final state, characterised by an isolated electron or muon and at least four jets. The search exploits the high multiplicity of jets containing b-hadrons, and deploys a neural network classifier that uses the kinematic differences between the signal and the background. The search uses a dataset of proton-proton collisions collected at a centre-of-mass energy s = 13 TeV between 2015 and 2018 with the ATLAS detector at CERN’s Large Hadron Collider, amounting to an integrated luminosity of 139 fb−1. Observed (expected) 95% confidence-level upper limits between 0.15% (0.09%) and 0.42% (0.25%) are derived for the product of branching fractions B (t → H±b) × B(H± → cb) for charged Higgs boson masses between 60 and 160 GeV, assuming the SM production of the top-quark pairs
Measurement of the and cross-sections in pp collisions at TeV with the ATLAS detector
No full textThe inclusive Higgs boson production cross-section is measured in the di-photon and the decay channels using 31.4 and 29.0 fb of pp collision data respectively, collected with the ATLAS detector at a centre-of-mass energy of . To reduce the model dependence, the measurement in each channel is restricted to a particle-level phase space that closely matches the channel’s detector-level kinematic selection, and it is corrected for detector effects. These measured fiducial cross-sections are fb, and fb, in agreement with the corresponding Standard Model predictions of fb and fb. Assuming Standard Model acceptances and branching fractions for the two channels, the fiducial measurements are extrapolated to the full phase space yielding total cross-sections of pb and pb at 13.6 from the di-photon and measurements respectively. The two measurements are combined into a total cross-section measurement of pb, to be compared with the Standard Model prediction of pb
Search for triple Higgs boson production in the 6 b final state using p p collisions at s = 13 TeV with the ATLAS detector
No full textA search for the production of three Higgs bosons ( H H H ) in the b b ¯ b b ¯ b b ¯ final state is presented. The search uses 126 fb − 1 of proton-proton collision data at s = 13 TeV collected with the ATLAS detector at the Large Hadron Collider. The analysis targets both nonresonant and resonant production of H H H . The resonant interpretations primarily consider a cascade decay topology of X → S H → H H H with masses of the new scalars X and S up to 1.5 and 1 TeV, respectively. In addition to scenarios where S is off-shell, the nonresonant interpretation includes a search for Standard Model H H H production, with limits on the trilinear and quartic Higgs self-coupling set. No evidence for H H H production is observed. An upper limit of 59 fb is set, at the 95% confidence level, on the cross section for Standard Model H H H production. © 2025 CERN, for the ATLAS Collaboration 2025 CER
Searches for lepton-flavour-violating decays of the Higgs boson into eτ and μτ in s = 13 TeV pp collisions with the ATLAS detector
No full textThis paper presents direct searches for lepton flavour violation in Higgs boson decays, H → eτ and H → μτ, performed using data collected with the ATLAS detector at the LHC. The searches are based on a data sample of proton-proton collisions at a centre-of-mass energy
s
= 13 TeV, corresponding to an integrated luminosity of 138 fb−1. Leptonic (τ → ℓνℓντ) and hadronic (τ → hadrons ντ) decays of the τ-lepton are considered. Two background estimation techniques are employed: the MC-template method, based on data-corrected simulation samples, and the Symmetry method, based on exploiting the symmetry between electrons and muons in the Standard Model backgrounds. No significant excess of events is observed and the results are interpreted as upper limits on lepton-flavour-violating branching ratios of the Higgs boson. The observed (expected) upper limits set on the branching ratios at 95% confidence level,
B
(H → eτ) < 0.20% (0.12%) and
B
(H → μτ ) < 0.18% (0.09%), are obtained with the MC-template method from a simultaneous measurement of potential H → eτ and H → μτ signals. The best-fit branching ratio difference,
B
(H → μτ) →
B
(H → eτ), measured with the Symmetry method in the channel where the τ-lepton decays to leptons, is (0.25 ± 0.10)%, compatible with a value of zero within 2.5σ
Measurement of the total and differential Higgs boson production cross-sections at s = 13 TeV with the ATLAS detector by combining the H → ZZ* → 4ℓ and H → γγ decay channels
No full textAbstract
The total and differential Higgs boson production cross-sections are measured through a combined statistical analysis of the H → ZZ* → 4ℓ and H → γγ decay channels. The results are based on a dataset of 139 fb−1 of proton–proton collisions at a centre-of-mass energy of 13 TeV, recorded by the ATLAS detector at the Large Hadron Collider. The measured total Higgs boson production cross-section is
55.5
−
3.8
+
4.0
pb, consistent with the Standard Model prediction of 55.6 ± 2.5 pb. All results from the two decay channels are compatible with each other, and their combination agrees with the Standard Model predictions. A combined statistical interpretation of the measured fiducial cross-sections as a function of the Higgs boson transverse momentum is performed in order to probe the Yukawa couplings to the bottom and charm quarks. A similar interpretation is performed by including also the constraints from the measurements of Higgs boson production in association with a W or Z boson in the H →
b
b
¯
and
c
c
¯
decay channels
Search for flavour-changing neutral tqH interactions with H → γγ in pp collisions at = 13 TeV using the ATLAS detector
No full textAbstract
A search for flavour-changing neutral interactions involving the top quark, the Higgs boson and an up-type quark q (q = c, u) is presented. The proton-proton collision data set used, with an integrated luminosity of 139 fb−1, was collected at = 13 TeV by the ATLAS experiment at the Large Hadron Collider. Both the decay process t → qH in production and the production process pp → tH, with the Higgs boson decaying into two photons, are investigated. No significant excess is observed and upper limits are set on the t → cH and the t → uH branching ratios of 4.3 × 10−4 and 3.8 × 10−4, respectively, at the 95% confidence level, while the expected limits in the absence of signal are 4.7 × 10−4 and 3.9 × 10−4. Combining this search with ATLAS searches in the H → τ+τ− and H → final states yields observed (expected) upper limits on the t → cH branching ratio of 5.8 × 10−4 (3.0 × 10−4) at the 95% confidence level. The corresponding observed (expected) upper limit on the t → uH branching ratio is 4.0 × 10−4 (2.4 × 10−4)
Search for dark matter produced in association with a single top quark and an energetic W boson in TeV collisions with the ATLAS detector
No full textThis paper presents a search for dark matter, χ , using events with a single top quark and an energetic W boson. The analysis is based on proton–proton collision data collected with the ATLAS experiment at s = 13 TeV during LHC Run 2 (2015–2018), corresponding to an integrated luminosity of 139 fb -1. The search considers final states with zero or one charged lepton (electron or muon), at least one b-jet and large missing transverse momentum. In addition, a result from a previous search considering two-charged-lepton final states is included in the interpretation of the results. The data are found to be in good agreement with the Standard Model predictions and the results are interpreted in terms of 95% confidence-level exclusion limits in the context of a class of dark matter models involving an extended two-Higgs-doublet sector together with a pseudoscalar mediator particle. The search is particularly sensitive to on-shell production of the charged Higgs boson state, H ± , arising from the two-Higgs-doublet mixing, and its semi-invisible decays via the mediator particle, a: H± → W ± a (→ χ χ ). Signal models with H ± masses up to 1.5 TeV and a masses up to 350 GeV are excluded assuming a tan β value of 1. For masses of a of 150 (250) GeV, tan β values up to 2 are excluded for H ± masses between 200 (400) GeV and 1.5 TeV. Signals with tan β values between 20 and 30 are excluded for H ± masses between 500 and 800 GeV
Search for heavy resonances in final states with four leptons and missing transverse momentum or jets in pp collisions at s = 13 TeV with the ATLAS detector
No full textAbstract A search for a new heavy boson produced via gluon-fusion in the four-lepton channel with missing transverse momentum or jets is performed. The search uses proton-proton collision data equivalent to an integrated luminosity of 139 fb−1 at a centre-of-mass energy of 13 TeV collected by the ATLAS detector between 2015 and 2018 at the Large Hadron Collider. This study explores the decays of heavy bosons: R → SH and A → ZH, where R is a CP-even boson, A is a CP-odd boson, H is a CP-even boson, and S is considered to decay into invisible particles that are candidates for dark matter. In these processes, S → invisible and H → ZZ. The Z boson associated with the heavy scalar boson H decays into all decay channels of the Z boson. The mass range under consideration is 390–1300 (320–1300) GeV for the R (A) boson and 220–1000 GeV for the H boson. No significant deviation from the Standard Model backgrounds is observed. The results are interpreted as upper limits at a 95% confidence level on the cross-section times the branching ratio of the heavy resonances
Search for dark photons from Higgs boson decays via ZH production with a photon plus missing transverse momentum signature from pp collisions at = 13 TeV with the ATLAS detector
No full textThis paper describes a search for dark photons (γd) in proton-proton collisions at s = 13 TeV at the Large Hadron Collider (LHC). The dark photons are searched for in the decay of Higgs bosons (H → γγd) produced through the ZH production mode. The transverse mass of the system, made of the photon and the missing transverse momentum from the non-interacting γd, presents a distinctive signature as it peaks near the Higgs boson mass. The results presented use the total Run-2 integrated luminosity of 139 fb−1 recorded by the ATLAS detector at the LHC. The dominant reducible background processes are estimated using data-driven techniques. A Boosted Decision Tree technique is adopted to enhance the sensitivity of the search. As no excess is observed with respect to the Standard Model prediction, an observed (expected) upper limit on the branching ratio BR(H → γγd) of 2.28% ( 2.82 − 0.84 + 1.33 % ) is set at 95% CL for massless γd. For massive dark photons up to 40 GeV, the observed (expected) upper limits on BR(H → γγd) at 95% confidence level is found within the [2.19,2.52]% ([2.71,3.11]%) range
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