A search for new physics in events featuring a single photon and missing transverse momentum is presented, using proton-proton <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msqrt><mi>s</mi></msqrt><mo>=</mo><mn>13</mn><mtext> </mtext><mtext> </mtext><mi>TeV</mi></math> collision data corresponding to an integrated luminosity of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mn>101</mn><mtext> </mtext><mtext> </mtext><msup><mi>fb</mi><mrow><mo>−</mo><mn>1</mn></mrow></msup></math> collected by the CMS experiment at the CERN LHC between 2017 and 2018. This analysis, combined with a previous study of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mn>36</mn><mtext> </mtext><mtext> </mtext><msup><mi>fb</mi><mrow><mo>−</mo><mn>1</mn></mrow></msup></math> of 2016 data (totaling <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mn>137</mn><mtext> </mtext><mtext> </mtext><msup><mi>fb</mi><mrow><mo>−</mo><mn>1</mn></mrow></msup></math>), reveals no significant deviations from standard model expectations. The results are then used to establish 95% confidence level limits on parameters in theoretical models involving dark matter and large extra dimensions. Compared to the 2016-only analysis, this search achieves up to a 14% improvement in exclusion reach for mediator masses in simplified dark matter models, along with 11% and 10% enhancements in the limits on the effective field theory suppression scale and the fundamental Planck scale, respectively. These results are the most stringent constraints on these parameters to date.

Armenia

A. Hayrapetyan

V. Makarenko

A. Tumasyan

Austria

W. Adam

J.W. Andrejkovic

L. Benato

T. Bergauer

M. Dragicevic

C. Giordano

P.S. Hussain

M. Jeitler

N. Krammer

A. Li

D. Liko

M. Matthewman

I. Mikulec

J. Schieck

R. Schöfbeck

D. Schwarz

M. Shooshtari

M. Sonawane

W. Waltenberger

C.E. Wulz

Belgium

T. Janssen

H. Kwon

D. Ocampo Henao

T. Van Laer

P. Van Mechelen

J. Bierkens

N. Breugelmans

J. D’Hondt

S. Dansana

A. De Moor

M. Delcourt

F. Heyen

Y. Hong

P. Kashko

S. Lowette

I. Makarenko

D. Müller

J. Song

S. Tavernier

M. Tytgat

G.P. Van Onsem

S. Van Putte

D. Vannerom

B. Bilin

B. Clerbaux

A.K. Das

I. De Bruyn

G. De Lentdecker

H. Evard

L. Favart

P. Gianneios

A. Khalilzadeh

F.A. Khan

A. Malara

M.A. Shahzad

L. Thomas

M. Vanden Bemden

C. Vander Velde

P. Vanlaer

F. Zhang

M. De Coen

D. Dobur

G. Gokbulut

J. Knolle

L. Lambrecht

D. Marckx

K. Skovpen

N. Van Den Bossche

J. van der Linden

J. Vandenbroeck

L. Wezenbeek

S. Bein

A. Benecke

A. Bethani

G. Bruno

A. Cappati

J. De Favereau De Jeneret

C. Delaere

A. Giammanco

A.O. Guzel

V. Lemaitre

J. Lidrych

P. Malek

P. Mastrapasqua

S. Turkcapar

Brazil

G.A. Alves

M. Barroso Ferreira Filho

E. Coelho

C. Hensel

T. Menezes De Oliveira

C. Mora Herrera

P. Rebello Teles

M. Soeiro

E.J. Tonelli Manganote

A. Vilela Pereira

W.L. Aldá Júnior

H. Brandao Malbouisson

Search for new physics in the final state with a single photon and large missing transverse momentum in proton-proton collisions at <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msqrt><mi>s</mi></msqrt><mo>=</mo><mn>13</mn><mtext> </mtext><mtext> </mtext><mi>TeV</mi></math>

We explore the leptonic sector of a recently proposed supersymmetric SO(10) model with supersymmetry breaking in the 3–10 TeV range. A new ingredient in this work is the requirement that the observed baryon asymmetry is explained via non-thermal leptogenesis, which can be realized in a large class of supersymmetric hybrid inflation models including SO(10). We provide estimates for the masses of the three Standard Model neutrinos (with the lightest mass $\textit{m}$ ≈ 5 meV) as well as the three right-handed neutrinos ($\textit{M}$ ≈ 10 GeV and $\textit{M}$ ≈ 10 GeV). The best fit estimate for the leptonic CP violating parameter $\textit{δ}$ ≈ 235$\textit{°}$, and the value of the neutrinoless double beta decay mass parameter $\textit{m}$ ≈ 0.18 meV. A numerical analysis broadens the predicted range for $\textit{δ}$ (100$\textit{°}$–300$\textit{°}$), but leaves largely intact the predictions for the six (light and heavy) neutrino masses and $\textit{m}$ . Our statistical analysis, which yields the likelihood-predicted ranges of the observables, is fully consistent with JUNO’s newly released first measurement of reactor neutrino oscillations in the $$ \Delta {m}_{12}^2 $$ -sin $\textit{θ}$ plane, with JUNO improving the precision by a factor of 1.6 relative to the combination of all previous measurements. The implementation of successful non-thermal leptogenesis allows us to provide estimates for the inflaton mass ($\textit{m}$ ≈ 7 × 10 GeV) and the reheating temperature ($\textit{T}$ ≈ 4 × 10 GeV).

Slovenia

Shaikh Saad

United States

Qaisar Shafi

Neutrino masses, $\textit{δ}$ PMNS, and $\textit{m}$ $\textit{ββ}$ in SO(10)

At hadron colliders, the net transverse momentum of particles that do not interact with the detector (missing transverse momentum, <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msubsup><mover accent="true"><mi>p</mi><mo stretchy="false">→</mo></mover><mi mathvariant="normal">T</mi><mrow><mi>miss</mi></mrow></msubsup></math>) is a crucial observable in many analyses. In the standard model, <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msubsup><mover accent="true"><mi>p</mi><mo stretchy="false">→</mo></mover><mi mathvariant="normal">T</mi><mrow><mi>miss</mi></mrow></msubsup></math> originates from neutrinos. Many beyond-the-standard-model particles, such as dark matter candidates, are also expected to leave the experimental apparatus undetected. This paper presents a novel deep neural network based <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msubsup><mover accent="true"><mi>p</mi><mo stretchy="false">→</mo></mover><mi mathvariant="normal">T</mi><mrow><mi>miss</mi></mrow></msubsup></math> estimator, deepmet, developed by the CMS Collaboration at the LHC. The deepmet algorithm produces a weight for each reconstructed particle based on its properties. The estimator is based on the negative vector sum of the weighted transverse momenta of all reconstructed particles in an event. Compared with other estimators currently employed by CMS, deepmet improves the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msubsup><mover accent="true"><mi>p</mi><mo stretchy="false">→</mo></mover><mi mathvariant="normal">T</mi><mrow><mi>miss</mi></mrow></msubsup></math> resolution by 10%–30%, shows improvement for a wide range of final states, is easier to train, and is more resilient against the effects of additional proton-proton interactions accompanying the collision of interest.

A.M. Tomaru

Improving missing transverse momentum estimation with a deep neural network

A measurement of the substructure of bottom quark jets (b jets) in proton-proton (pp) collisions is presented. The measurement uses data collected in pp collisions at $$ \sqrt{s}=5.02 $$ TeV, with a low number of simultaneous interactions per bunch crossing, recorded by the CMS experiment in 2017, corresponding to an integrated luminosity of 301 pb . An algorithm to identify and cluster the charged decay daughters of b hadrons is developed for this analysis, which facilitates the exposure of the gluon radiation pattern of b jets using iterative Cambridge-Aachen declustering. The soft-drop-groomed jet radius, $\textit{R}$ , and momentum balance, $\textit{z}$ , of b quark jets are presented. These observables can be used to test perturbative quantum chromodynamics predictions that account for mass effects. Because the b hadron is partially reconstructed from its charged decay daughters, only charged particles are used for the jet substructure studies. In addition, a jet fragmentation function, $\textit{z}$ , is measured, which is defined as the distribution of the ratio of the transverse momentum ($\textit{p}$ ) of the partially reconstructed b hadron with respect to the charged-particle component of the jet $\textit{p}$ . The substructure variable distributions are unfolded to the charged-particle level. The b jet substructure is compared to the substructure of jets in an inclusive jet sample that is dominated by light-quark and gluon jets in order to assess the role of the b quark mass. A strong suppression of emissions at small $\textit{R}$ values is observed for b jets when compared to inclusive jets, consistent with the dead-cone effect. The measurement is also compared with theoretical predictions from Monte Carlo event generators. This is the first substructure measurement of b jets that clusters together the b hadron decay daughters independent of the b hadron species and decay channel.

V. Chekhovsky

J. Andrejkovic

S. Chatterjee

K. Damanakis

P. Hussain

T. Laer

P. Mechelen

A. Moor

G. Onsem

S. Putte

A. Das

I. Bruyn

G. Lentdecker

F. Khan

M. Shahzad

M. Bemden

M. Coen

N. Bossche

J. Linden

C. Caputo

I. Donertas

A. Guzel

Sa. Jain

T. Tran

G. Alves

G. Correia Silva

E. Tonelli Manganote

W. Aldá Júnior

W. Carvalho

J. Chinellato

Jet fragmentation function and groomed substructure of bottom quark jets in proton-proton collisions at 5.02 TeV

A search is presented for narrow resonances, with a mass between 0.6 and 1.8 TeV, decaying to pairs of jets, in proton-proton collisions at $$ \sqrt{s}=13 $$ TeV. The search is performed using dijets that are reconstructed, selected, and recorded in a compact form by the high-level trigger in a technique referred to as “data scouting”, from data collected in 2016–2018 corresponding to an integrated luminosity of 117 fb . The dijet mass spectra are well described by a smooth parameterization, and no significant evidence for the production of new particles is observed. Model-independent upper limits are presented on the product of the cross section, branching fraction, and acceptance for the individual cases of narrow quark-quark, quark-gluon, and gluon-gluon resonances, and are compared to the predictions from a variety of models of narrow dijet resonance production. The upper limit on the coupling of a dark matter mediator to quarks is presented as a function of the mediator mass. The sensitivity of this search goes beyond what is expected from statistical scaling with the integrated luminosity alone, as a consequence of the use of fewer parameters in the background function within a more robust statistical procedure.

Search for dijet resonances with data scouting in proton-proton collisions at $$ \sqrt{s}=13 $$ TeV

A search for a pair of light pseudoscalar bosons (a ) produced in the decay of the 125 GeV Higgs boson is presented. The analysis examines decay modes where one a decays into a pair of tau leptons and the other decays into either another pair of tau leptons or a pair of muons. The a boson mass probed in this study ranges from 4 to 15 GeV. The data sample was recorded by the CMS experiment in proton-proton collisions at a center-of-mass energy of 13 TeV and corresponds to an integrated luminosity of 138 fb . No excess above standard model (SM) expectations is observed. The study combines the 4τ and 2μ2τ channels to set upper limits at 95% confidence level (CL) on the product of the Higgs boson production cross section and the branching fraction to the 4τ final state, relative to the Higgs boson production cross section predicted by the SM. In this interpretation, the a boson is assumed to have Yukawa-like couplings to fermions, with coupling strengths proportional to the respective fermion masses. The observed (expected) upper limits range between 0.007 (0.011) and 0.079 (0.066) across the mass range considered. The results are also interpreted in the context of models with two Higgs doublets and an additional complex singlet field (2HD+S). The tightest constraints are obtained for the Type III 2HD+S model. In this case, assuming the Higgs boson production cross section equals the SM prediction, values of the branching ratio for the Higgs boson decay into a pair of a bosons exceeding 16% are excluded at 95% CL for a boson masses between 5 and 15 GeV and tan $\textit{β >}$ 2, with the exception of scenarios in which the a boson mixes with charm or bottom quark-antiquark bound states.

Search for light pseudoscalar boson pairs produced from Higgs boson decays using the 4τ and 2μ2τ final states in proton-proton collisions at $$ \sqrt{s}=13 $$ TeV

Precision measurements of Higgs boson differential production cross sections are a key tool to probe the properties of the Higgs boson and test the standard model. New physics can affect both Higgs boson production and decay, leading to deviations from the distributions that are expected in the standard model. In this paper, combined measurements of differential spectra in a fiducial region matching the experimental selections are performed, based on analyses of four Higgs boson decay channels (γγ, ZZ , WW , and ττ) using proton-proton collision data recorded with the CMS detector at $$ \sqrt{s}=13 $$ TeV, corresponding to an integrated luminosity of 138 fb . The differential measurements are extrapolated to the full phase space and combined to provide the differential spectra. A measurement of the total Higgs boson production cross section is also performed using the γγ and ZZ decay channels, with a result of $$ {53.4}_{-2.9}^{+2.9}{\left(\textrm{stat}\right)}_{-1.8}^{+1.9}\left(\textrm{syst}\right) $$ pb, consistent with the standard model prediction of 55.6 ± 2.5 pb. The fiducial measurements are used to compute limits on Higgs boson couplings using the $\textit{κ}$-framework and the SM effective field theory.

Combination and interpretation of differential Higgs boson production cross sections in proton-proton collisions at $$ \sqrt{s}=13 $$ TeV

Inclusive and differential cross section measurements of top quark pair ( $$ \textrm{t}\overline{\textrm{t}} $$ ) production in association with a photon (γ) are performed as a function of lepton, photon, top quark, and $$ \textrm{t}\overline{\textrm{t}} $$ kinematic observables, using data from proton-proton collisions at $$ \sqrt{s}=13 $$ TeV, corresponding to an integrated luminosity of 138 fb , collected at the CERN LHC with the CMS detector. Events containing two leptons (electrons or muons) and a photon in the final state are considered. The fiducial cross section of $$ \textrm{t}\overline{\textrm{t}}\upgamma $$ is measured to be 137 ± 8 fb, in a phase space including events with a high momentum, isolated photon. The fiducial cross section of $$ \textrm{t}\overline{\textrm{t}}\upgamma $$ is also measured to be 56 ± 5 fb when considering only events where the photon is emitted in the production part of the process. Both measurements are in agreement with the theoretical predictions, of 126 ± 19 fb and 57 ± 5 fb, respectively. Differential measurements are performed at the particle and parton levels. Additionally, inclusive and differential ratios between the cross sections of $$ \textrm{t}\overline{\textrm{t}}\upgamma $$ and $$ \textrm{t}\overline{\textrm{t}} $$ production are measured. The inclusive ratio is found to be 0.0133 ± 0.0005, in agreement with the standard model prediction of 0.0127 ± 0.0008. The top quark charge asymmetry in $$ \textrm{t}\overline{\textrm{t}}\upgamma $$ production is also measured to be −0.012 ± 0.042, compatible with both the standard model prediction and with no asymmetry.

A. Tomaru

F. Gameiro Casalinho

Inclusive and differential measurements of the $$ \textrm{t}\overline{\textrm{t}}\upgamma $$ cross section and the $$ \textrm{t}\overline{\textrm{t}}\upgamma /\textrm{t}\overline{\textrm{t}} $$ cross section ratio in proton-proton collisions at $$ \sqrt{s}=13 $$ TeV

In recent years, the resistive cylindrical chamber (RCC) has been introduced as a novel gaseous detector, extending the well-established resistive plate chambers (RPCs) to the case of cylindrical electrode geometry. Preliminary experimental studies, although still limited in number and performed under experimental conditions not always fully controlled, have nevertheless highlighted several promising features of this detector configuration, motivating the need for further systematic investigations of its operation. In contrast, from the simulation perspective, detailed studies of the RCC have not been performed yet, despite the fact that the cylindrical geometry introduces new degrees of freedom – such as cylinder electrodes radii and voltage polarity – which lead to asymmetric behaviour of the avalanche development according to the polarity of the applied voltage between the electrodes. In this work we present a standalone simulation program specifically designed to model avalanche growth and signal induction in both RPC and RCC geometries. The code implements a stepwise transport model for electron multiplication, includes approximate space-charge effects, and evaluates the induced signals on an external electrode. The simulation has been validated against experimental data for planar RPCs and subsequently applied to RCC geometries with the primary goal of investigating the underlying physical features of the cylindrical detector configuration. The results show that key observables such as induced charge and efficiency are well reproduced in the planar case, and they highlight the role of the electric-field asymmetry in shaping avalanche dynamics in the cylindrical geometry. A first comparison with available RCC experimental data is also presented, providing an initial assessment of the model performance in realistic operating conditions.

Italy

M. Abbrescia

S. Colafranceschi

M. Serio

B. Liberti

S. Meola

A. Paoloni

A. Pastore

D. Piccolo

A. Rocchi

G. Saviano

C. Vendittozzi

A standalone simulation program for resistive cylindrical chamber (RCC)

In all previous calculations of the nonlocal subleading contribution to the inclusive penguin decay <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mover accent="true"><mi>B</mi><mo stretchy="false">¯</mo></mover><mo stretchy="false">→</mo><msub><mi>X</mi><mi>s</mi></msub><mi>γ</mi></math> due to the interference of the electroweak operators <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msubsup><mi mathvariant="script">O</mi><mn>1</mn><mi>c</mi></msubsup><mo>−</mo><msub><mi mathvariant="script">O</mi><mrow><mn>7</mn><mi>γ</mi></mrow></msub></math> the local Voloshin term was subtracted. In view of the ongoing analysis at order <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>α</mi><mi>s</mi></msub></math>, we present a calculation of the complete nonlocal contribution which takes into account the high correlation between the uncertainties of the local Voloshin and the nonlocal term of the previous analyses. The new calculation has a high impact on the range of the nonlocal contribution.

Germany

Michael Benzke

Maria Vittoria Garzelli

Tobias Hurth

Addendum to “Resolved <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mn>1</mn><mo>/</mo><msub><mi>m</mi><mi>b</mi></msub></math> contributions to <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mover accent="true"><mi>B</mi><mo stretchy="false">¯</mo></mover><mo stretchy="false">→</mo><msub><mi>X</mi><mrow><mi>s</mi><mo>,</mo><mi>d</mi></mrow></msub><msup><mo>ℓ</mo><mo>+</mo></msup><msup><mo>ℓ</mo><mo>−</mo></msup></math> and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mover accent="true"><mi>B</mi><mo stretchy="false">¯</mo></mover><mo stretchy="false">→</mo><msub><mi>X</mi><mi>s</mi></msub><mi>γ</mi></math>”