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. Hayrapetyan

V. Makarenko

A. Tumasyan

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

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

D. Marckx

K. Skovpen

A.M. Tomaru

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

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

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.

Armenia

V. Chekhovsky

Austria

J. Andrejkovic

S. Chatterjee

K. Damanakis

P. Hussain

Belgium

T. Laer

P. Mechelen

A. Moor

G. Onsem

S. Putte

A. Das

I. Bruyn

G. Lentdecker

F. Khan

M. Shahzad

M. Bemden

M. Coen

L. Lambrecht

N. Bossche

J. Linden

C. Caputo

I. Donertas

A. Guzel

Sa. Jain

T. Tran

Brazil

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 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

We study a five-leg scattering amplitude on the special Coulomb branch of planar <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mi mathvariant="script">N</mi><mo>=</mo><mn>4</mn></mrow></math> super Yang-Mills theory. We reach this point of the moduli space of scalar vacuum expectation values by considering six-dimensional <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi mathvariant="script">N</mi><mo>=</mo><mo stretchy="false">(</mo><mn>1</mn><mo>,</mo><mn>1</mn><mo stretchy="false">)</mo></math> super Yang-Mills theory and reducing it down to four space-time dimensions with extradimensional momenta being nonvanishing. This branch is characterized by massive external W-bosons and massless internal gluons propagating in loops. We analyze the five W-boson amplitude in the kinematics when their masses are much smaller than all Mandelstam-like invariants. This is what we dub the near mass-shell limit. We perform calculations to two-loop order in ’t Hooft coupling, making use of recent advances in analytic calculations of required Feynman integrals. Our findings confirm exponentiation of infrared logarithms and enable us to conjecture a concise all-order expression for the amplitude in question. We further analyze its duality to the square root of a five-point correlation function of infinitely heavy half-BPS (Bogomol’nyi–Prasad–Sommerfield) operators, known as the decagon. By considering the near-null limit for inter-operators distances, we verify that the two objects coincide. This observation corroborates the novel Coulomb amplitudes/heavy correlator duality previously observed for four W-boson amplitudes and Sudakov form factors.

A.V. Belitsky

L.V. Bork

R.N. Lee

A.I. Onishchenko

V.A. Smirnov

Five W-boson amplitude is equal to near-null decagon

Constraints on Wilson coefficients (WCs) corresponding to dimension-6 operators of the standard model effective field theory (SMEFT) are determined from a simultaneous fit to seven sets of CMS measurements probing Higgs boson, electroweak vector boson, top quark, and multijet production. Measurements of electroweak precision observables are also included and provide complementary constraints to those from the CMS experiment. The CMS measurements, using LHC proton-proton collision data at $$\sqrt{s}=13\,\text {Te}\text {V} $$ , corresponding to integrated luminosities of 36.3 or 138 $$\,\text {fb}^{-1}$$ , are chosen to provide sensitivity to a broad set of operators, for which consistent SMEFT predictions can be derived. These are primarily measurements of differential cross sections which are parameterized as functions of the WCs. In measurements targeting $${\text {t}} (\bar{\textrm{t}})\text {X} $$ production, SMEFT effects are modelled at the detector level. Individual constraints on 64 WCs, and constraints on 43 linear combinations of WCs, are obtained.

J. Favereau De Jeneret

Combined effective field theory interpretation of Higgs boson, electroweak vector boson, top quark, and multijet measurements

We achieve for the first time NNLO <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mi>QCD</mi><mo>+</mo><mi>NLO</mi></mrow></math> EW accuracy for doubly polarized <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>W</mi><mi>Z</mi></math> inclusive production at the LHC, in the case of fully leptonic decays. Additionally, we provide estimates for missing higher-order uncertainties in QCD associated with doubly polarized differential cross sections and joint polarization fractions, obtained both with standard scale variations and with a theory-nuisance-parameter approach. The study is carried out in the fiducial setup of a recent ATLAS analysis of Run-2 data.

Giovanni Pelliccioli

Rene Poncelet

Precise predictions for joint polarization fractions in <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>W</mi><mi>Z</mi></math> production at the LHC

As a strong candidate for new physics beyond the Standard Model, the exotic charged gauge boson <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mi>W</mi><mo>′</mo></msup></math> has attracted extensive research interest. In this work, we investigate the interactions of the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mi>W</mi><mo>′</mo></msup></math> boson at the electron-proton colliders. The process <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mi>e</mi><mo>−</mo></msup><mi>u</mi><mo stretchy="false">→</mo><msub><mi>ν</mi><mi>e</mi></msub><mi>d</mi></math> and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mi>e</mi><mo>−</mo></msup><mi>u</mi><mo stretchy="false">→</mo><msup><mi>e</mi><mo>±</mo></msup><mi>j</mi><mi>j</mi><mi>j</mi></math> with <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>t</mi></math>-channel <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mi>W</mi><mo>′</mo></msup></math> exchange are studied. The polarization of the initial-state electrons has a significant impact on the cross section of the studied process, while the angular distribution of the final-state leptons serves as an important observable for the interactions of the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mi>W</mi><mo>′</mo></msup></math> boson. In some specific regions of the parameter space, the detectable mass range for the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mi>W</mi><mo>′</mo></msup></math> boson can reach around 10 TeV, and the coupling strength can achieve a precision of approximately 1% relative to the interaction strength of the Standard Model. Especially, <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mi>e</mi><mo>−</mo></msup><mi>u</mi><mo stretchy="false">→</mo><msup><mi>e</mi><mo>+</mo></msup><mi>j</mi><mi>j</mi><mi>j</mi></math> process is forbidden within the Standard Model, which would constitute important evidence in the search for the left-right symmetric model.

Xinyi Yan

Honglei Li

Zhi-Long Han

Fei Huang

Ruiyu Xing

Study the property of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mi>W</mi><mo>′</mo></msup></math> at future <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mi>e</mi><mo>−</mo></msup><mi>p</mi></math> collider

A search for signatures of a dark analog to quantum chromodynamics is performed. The analysis targets long-lived dark mesons that decay into standard-model particles, with a high branching fraction of the dark mesons decaying into muons. The dark mesons are formed by the hadronisation of dark partons, which are produced by a decay of the Higgs boson. The search is performed using a data set corresponding to an integrated luminosity of 41.6 fb , which was collected in proton-proton collisions at $$ \sqrt{s}=13 $$ TeV by the CMS experiment at the CERN LHC in 2018 using non-prompt muon triggers. The search is based on resonant muon pair signatures. Machine-learning techniques are employed in the analysis, utilising boosted decision trees to discriminate between signal and background. No significant excess is observed above the standard model expectation. Upper limits on the branching fraction of the Higgs boson decaying to dark partons are determined to be as low as 10 at 95% confidence level, surpassing and extending the existing limits on models with dark $$ \overset{\sim }{\upomega} $$ mesons for mean proper decay lengths of less than 500 mm and for $$ \overset{\sim }{\upomega} $$ masses down to 0.3 GeV. First limits are set for extended dark-shower models with two dark flavours that contain dark photons, probing their masses down to 0.33 GeV.

Search for low-mass hidden-valley dark showers with non-prompt muon pairs in proton-proton collisions at $$ \sqrt{s}=13 $$ TeV