Rodrigo Gamboa Goñi

• Full time professor at Tecnológico de Monterrey

A bstract A search for flavour-changing neutral-current decays of a top quark into an up-type quark (either up or charm) and a light scalar particle X decaying into a bottom anti-bottom quark pair is presented. The search focuses on top-quark pair production where one top quark decays to qX , with X → $$ b\overline{b} $$ b b ¯ , and the other top q...

A bstract A search for a new heavy scalar or pseudo-scalar Higgs boson ( H/A ) produced in association with a pair of top quarks, with the Higgs boson decaying into a pair of top quarks ( H/A → $$ t\overline{t} $$ t t ¯ ) is reported. The search targets a final state with exactly two leptons with same-sign electric charges or at least three leptons...

A bstract A search for resonances in events with at least one isolated lepton ( e or μ ) and two jets is performed using 139 fb − 1 of $$ \sqrt{s} $$ s = 13 TeV proton–proton collision data recorded by the ATLAS detector at the LHC. Deviations from a smoothly falling background hypothesis are tested in three- and four-body invariant mass distributi...

A bstract This paper describes a search for dark photons ( γ d ) in proton-proton collisions at $$ \sqrt{s} $$ s = 13 TeV at the Large Hadron Collider (LHC). The dark photons are searched for in the decay of Higgs bosons ( H → γγ d ) produced through the ZH production mode. The transverse mass of the system, made of the photon and the missing trans...

A bstract Differential and double-differential distributions of kinematic variables of leptons from decays of top-quark pairs ( $$ t\overline{t} $$ t t ¯ ) are measured using the full LHC Run 2 data sample collected with the ATLAS detector. The data were collected at a pp collision energy of $$ \sqrt{s} $$ s = 13 TeV and correspond to an integrated...

A bstract A search for high-mass charged and neutral bosons decaying to Wγ and Zγ final states is presented in this paper. The analysis uses a data sample of $$ \sqrt{s} $$ s = 13 TeV proton-proton collisions with an integrated luminosity of 139 fb − 1 collected by the ATLAS detector during LHC Run 2 operation. The sensitivity of the search is dete...

A bstract A search for vector-like leptons in multilepton (two, three, or four-or-more electrons plus muons) final states with zero or more hadronic τ -lepton decays is presented. The search is performed using a dataset corresponding to an integrated luminosity of 139 fb − 1 of proton-proton collisions at a centre-of-mass energy of 13 TeV recorded...

A bstract Several extensions of the Standard Model predict the production of dark matter particles at the LHC. A search for dark matter particles produced in association with a dark Higgs boson decaying into W ⁺ W − in the $$ {\ell}^{\pm}\nu q{\overline{q}}^{\prime }, $$ ℓ ± νq q ¯ ′ , final states with ℓ = e, μ is presented. This analysis uses 139...

A bstract This paper presents a search for a new Z ′ vector gauge boson with the ATLAS experiment at the Large Hadron Collider using pp collision data collected at $$ \sqrt{s} $$ s = 13 TeV, corresponding to an integrated luminosity of 139 fb − 1 . The new gauge boson Z ′ is predicted by L μ − L τ models to address observed phenomena that can not b...

A bstract Measurements of differential cross sections are presented for inclusive isolated-photon production in pp collisions at a centre-of-mass energy of 13 TeV provided by the LHC and using 139 fb − 1 of data recorded by the ATLAS experiment. The cross sections are measured as functions of the photon transverse energy in different regions of pho...

A bstract Measurements of Higgs boson production cross-sections are carried out in the diphoton decay channel using 139 fb − 1 of pp collision data at $$ \sqrt{s} $$ s = 13 TeV collected by the ATLAS experiment at the LHC. The analysis is based on the definition of 101 distinct signal regions using machine-learning techniques. The inclusive Higgs b...

A bstract This paper presents measurements of charged-hadron spectra obtained in pp , p +Pb, and Pb+Pb collisions at $$ \sqrt{s} $$ s or $$ \sqrt{s_{\textrm{NN}}} $$ s NN = 5 . 02 TeV, and in Xe+Xe collisions at $$ \sqrt{s_{\textrm{NN}}} $$ s NN = 5 . 44 TeV. The data recorded by the ATLAS detector at the LHC have total integrated luminosities of 2...

A bstract Differential cross-section measurements of Zγ production in association with hadronic jets are presented, using the full 139 fb − 1 dataset of $$ \sqrt{s} $$ s = 13 TeV proton–proton collisions collected by the ATLAS detector during Run 2 of the LHC. Distributions are measured using events in which the Z boson decays leptonically and the...

A bstract A search for the leptonic charge asymmetry ( $$ {A}_{\textrm{c}}^{\ell } $$ A c ℓ ) of top-quark-antiquark pair production in association with a W boson ( $$ t\overline{t}W $$ t t ¯ W ) is presented. The search is performed using final states with exactly three charged light leptons (electrons or muons) and is based on $$ \sqrt{s} $$ s =...

A bstract A search for Higgs boson pair production in events with two b -jets and two τ -leptons is presented, using a proton–proton collision dataset with an integrated luminosity of 139 fb − 1 collected at $$ \sqrt{s} $$ s = 13 TeV by the ATLAS experiment at the LHC. Higgs boson pairs produced non-resonantly or in the decay of a narrow scalar res...

A bstract A search for new phenomena has been performed in final states with at least one isolated high-momentum photon, jets and missing transverse momentum in proton–proton collisions at a centre-of-mass energy of $$ \sqrt{s} $$ s = 13 TeV. The data, collected by the ATLAS experiment at the CERN LHC, correspond to an integrated luminosity of 139...

A bstract A search for long-lived particles decaying into hadrons is presented. The analysis uses 139 fb − 1 of pp collision data collected at $$ \sqrt{s} $$ s = 13 TeV by the ATLAS detector at the LHC using events that contain multiple energetic jets and a displaced vertex. The search employs dedicated reconstruction techniques that significantly...

A bstract Exclusive production of dielectron pairs, γγ → e ⁺ e − , is studied using $$ {\mathcal{L}}_{\textrm{int}} $$ L int = 1 . 72 nb − 1 of data from ultraperipheral collisions of lead nuclei at $$ \sqrt{s_{\textrm{NN}}} $$ s NN = 5 . 02 TeV recorded by the ATLAS detector at the LHC. The process of interest proceeds via photon–photon interactio...

A bstract A measurement of single top-quark production in the s-channel is performed in proton–proton collisions at a centre-of-mass energy of 13 TeV with the ATLAS detector at the CERN Large Hadron Collider. The dataset corresponds to an integrated luminosity of 139 fb − 1 . The analysis is performed on events with an electron or muon, missing tra...

A bstract A search for pair-produced scalar and vector leptoquarks decaying into quarks and leptons of different generations is presented. It uses the full LHC Run 2 (2015–2018) data set of 139 fb − 1 collected with the ATLAS detector in proton–proton collisions at a centre-of-mass energy of $$ \sqrt{s} $$ s = 13 TeV. Scalar leptoquarks with charge...

A bstract A search for light long-lived neutral particles with masses in the O (MeV–GeV) range is presented. The analysis targets the production of long-lived dark photons in the decay of a Higgs boson produced via gluon–gluon fusion or in association with a W boson. Events that contain displaced collimated Standard Model fermions reconstructed in...

A bstract The inclusive top-quark pair ( $$ t\overline{t} $$ t t ¯ ) production cross-section $$ {\sigma}_{t\overline{t}} $$ σ t t ¯ is measured in proton–proton collisions at a centre-of-mass energy $$ \sqrt{s} $$ s = 5 . 02 TeV, using 257 pb − 1 of data collected in 2017 by the ATLAS experiment at the LHC. The $$ t\overline{t} $$ t t ¯ cross-sect...

A bstract A search for flavour-changing neutral current (FCNC) tqH interactions involving a top quark, another up-type quark ( q = u, c ), and a Standard Model (SM) Higgs boson decaying into a τ -lepton pair ( H → τ ⁺ τ − ) is presented. The search is based on a dataset of pp collisions at $$ \sqrt{s} $$ s = 13 TeV that corresponds to an integrated...

A bstract The electroweak production of $$ Z\left(\nu \overline{\nu}\right)\gamma $$ Z ν ν ¯ γ in association with two jets is studied in a regime with a photon of high transverse momentum above 150 GeV using proton–proton collisions at a centre-of-mass energy of 13 TeV at the Large Hadron Collider. The analysis uses a data sample with an integrate...

A bstract Cross-section measurements for a Z boson produced in association with high-transverse-momentum jets ( p T ≥ 100 GeV) and decaying into a charged-lepton pair ( e ⁺ e − , μ ⁺ μ − ) are presented. The measurements are performed using proton–proton collisions at $$ \sqrt{s} $$ s = 13 TeV corresponding to an integrated luminosity of 139 fb − 1...

A bstract A generic search for resonances is performed with events containing a Z boson with transverse momentum greater than 100 GeV, decaying into e ⁺ e − or μ ⁺ μ − . The analysed data collected with the ATLAS detector in proton-proton collisions at a centre-of-mass energy of 13 TeV at the Large Hadron Collider correspond to an integrated lumino...

A bstract A search for the electroweak production of pairs of charged sleptons or charginos decaying into two-lepton final states with missing transverse momentum is presented. Two simplified models of R -parity-conserving supersymmetry are considered: direct pair-production of sleptons $$ \left(\overset{\sim }{\ell}\overset{\sim }{\ell}\right) $$...

A bstract This article presents a search for new resonances decaying into a Z or W boson and a 125 GeV Higgs boson h , and it targets the $$ \nu \overline{\nu}b\overline{b} $$ ν ν ¯ b b ¯ , $$ {\ell}^{+}{\ell}^{-}b\overline{b} $$ ℓ + ℓ − b b ¯ , or $$ {\ell}^{\pm}\nu b\overline{b} $$ ℓ ± νb b ¯ final states, where ℓ = e or μ , in proton-proton coll...

A bstract A measurement of the top-quark mass ( m t ) in the $$ t\overline{t} $$ t t ¯ → lepton + jets channel is presented, with an experimental technique which exploits semileptonic decays of b -hadrons produced in the top-quark decay chain. The distribution of the invariant mass m ℓμ of the lepton, ℓ (with ℓ = e, μ ), from the W -boson decay and...

A measurement of the polarisation of W bosons produced in top-quark decays is presented, using proton–proton collision data at a centre-of-mass energy of s=13 TeV. The data were collected by the ATLAS detector at the Large Hadron Collider and correspond to an integrated luminosity of 139 fb⁻¹. The measurement is performed selecting tt¯ events decay...

A bstract The total and differential Higgs boson production cross-sections are measured through a combined statistical analysis of the H → ZZ * → 4 ℓ 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 Collide...

A bstract Measurements of single-, double-, and triple-differential cross-sections are presented for boosted top-quark pair-production in 13 TeV proton–proton collisions recorded by the ATLAS detector at the LHC. The top quarks are observed through their hadronic decay and reconstructed as large-radius jets with the leading jet having transverse mo...

Electroweak symmetry breaking explains the origin of the masses of elementary particles through their interactions with the Higgs field. Besides the measurements of the Higgs boson properties, the study of the scattering of massive vector bosons with spin 1 allows the nature of electroweak symmetry breaking to be probed. Among all processes related...

A bstract A simultaneous measurement of the three components of the top-quark and top-antiquark polarisation vectors in t -channel single-top-quark production is presented. This analysis is based on data from proton–proton collisions at a centre-of-mass energy of 13 TeV corresponding to an integrated luminosity of 139 fb − 1 , collected with the AT...

A simultaneous measurement of the three components of the top-quark and top-antiquark polarisation vectors in t-channel single-top-quark production is presented. This analysis is based on data from proton–proton collisions at a centre-of-mass energy of 13 TeV corresponding to an integrated luminosity of 139 fb−1, collected with the ATLAS detector a...

A search for the pair production of heavy leptons as predicted by the type-III seesaw mechanism is presented. The search uses proton–proton collision data at a centre-of-mass energy of 13 TeV, corresponding to 139fb-1 of integrated luminosity recorded by the ATLAS detector during Run 2 of the Large Hadron Collider. The analysis focuses on final sta...

Searches are performed for nonresonant and resonant di-Higgs boson production in the bb¯γγ final state. The dataset used corresponds to an integrated luminosity of 139 fb−1 of proton–proton collisions at a center-of-mass energy of 13 TeV recorded by the ATLAS detector at the CERN Large Hadron Collider. No excess above the expected background is fou...

A bstract Measurements of the production cross-sections of the Standard Model (SM) Higgs boson ( H ) decaying into a pair of τ -leptons are presented. The measurements use data collected with the ATLAS detector from pp collisions produced at the Large Hadron Collider at a centre-of-mass energy of $$ \sqrt{s} $$ s = 13 TeV, corresponding to an integ...

Several observables sensitive to the fragmentation of b quarks into b hadrons are measured using 36 fb−1 of s=13 TeV proton-proton collision data collected with the ATLAS detector at the LHC. Jets containing b hadrons are obtained from a sample of dileptonic tt¯ events, and the associated set of charged-particle tracks is separated into those from...

A search for events with two displaced vertices from long-lived particle (LLP) pairs using data collected by the ATLAS detector at the LHC is presented. This analysis uses 139 fb−1 of proton-proton collision data at s=13 TeV recorded in 2015–2018. The search employs techniques for reconstructing vertices of LLPs decaying to jets in the muon spectro...

A bstract A direct search for Higgs bosons produced via vector-boson fusion and subsequently decaying into invisible particles is reported. The analysis uses 139 fb − 1 of pp collision data at a centre-of-mass energy of $$ \sqrt{s} $$ s = 13 TeV recorded by the ATLAS detector at the LHC. The observed numbers of events are found to be in agreement w...

A bstract A study of $$ {B}_c^{+}\to J/\psi {D}_s^{+} $$ B c + → J / ψ D s + and $$ {B}_c^{+}\to J/\psi {D}_s^{\ast +} $$ B c + → J / ψ D s ∗ + decays using 139 fb − 1 of integrated luminosity collected with the ATLAS detector from $$ \sqrt{s} $$ s = 13 TeV pp collisions at the LHC is presented. The ratios of the branching fractions of the two deca...

A bstract This paper presents updated Monte Carlo configurations used to model the production of single electroweak vector bosons ( W , Z/γ ∗ ) in association with jets in proton-proton collisions for the ATLAS experiment at the Large Hadron Collider. Improvements pertaining to the electroweak input scheme, parton-shower splitting kernels and scale...

A study of B+c→J/ψD+s and B+c→J/ψD∗+s decays using 139 fb−1 of integrated luminosity collected with the ATLAS detector from s√ = 13 TeV pp collisions at the LHC is presented. The ratios of the branching fractions of the two decays to the branching fraction of the B+c → J/ψπ+ decay are measured: B(B+c→J/ψD+s)/B(B+c→J/ψπ+) = 2.76 ± 0.47 and B(B+c→J/ψ...

This Letter reports the observation of WWW production and a measurement of its cross section using 139 fb−1 of proton-proton collision data recorded at a center-of-mass energy of 13 TeV by the ATLAS detector at the Large Hadron Collider. Events with two same-sign leptons (electrons or muons) and at least two jets, as well as events with three charg...

A bstract A measurement of inclusive and differential fiducial cross-sections for the production of the Higgs boson decaying into two photons is performed using 139 fb − 1 of proton-proton collision data recorded at $$ \sqrt{s} $$ s = 13 TeV by the ATLAS experiment at the Large Hadron Collider. The inclusive cross-section times branching ratio, in...

A search for the Higgs boson decaying into a pair of charm quarks is presented. The analysis uses proton–proton collisions to target the production of a Higgs boson in association with a leptonically decaying W or Z boson. The dataset delivered by the LHC at a centre-of-mass energy of and recorded by the ATLAS detector corresponds to an integrated...

A search for the Higgs boson decaying into a pair of charm quarks is presented. The analysis uses proton–proton collisions to target the production of a Higgs boson in association with a leptonically decaying W or Z boson. The dataset delivered by the LHC at a centre-of-mass energy of and recorded by the ATLAS detector corresponds to an integrated...

This paper presents studies of Bose–Einstein correlations (BEC) in proton–proton collisions at a centre-of-mass energy of 13 TeV, using data from the ATLAS detector at the CERN Large Hadron Collider. Data were collected in a special low-luminosity configuration with a minimum-bias trigger and a high-multiplicity track trigger, accumulating integrat...

A search for long-lived charginos produced either directly or in the cascade decay of heavy prompt gluino states is presented. The search is based on proton–proton collision data collected at a centre-of-mass energy of s = 13 TeV between 2015 and 2018 with the ATLAS detector at the LHC, corresponding to an integrated luminosity of 136 fb-1. Long-li...

This article presents the results of two studies of Higgs boson properties using the WW∗(→eνμν)jj final state, based on a dataset corresponding to 36.1fb-1 of s=13 TeV proton–proton collisions recorded by the ATLAS experiment at the Large Hadron Collider. The first study targets Higgs boson production via gluon–gluon fusion and constrains the CP pr...

The azimuthal variation of jet yields in heavy-ion collisions provides information about the path-length dependence of the energy loss experienced by partons passing through the hot, dense nuclear matter known as the quark–gluon plasma. This paper presents the azimuthal anisotropy coefficients v2, v3, and v4 measured for jets in Pb + Pb collisions...

A bstract A search for decays of pair-produced neutral long-lived particles (LLPs) is presented using 139 fb − 1 of proton-proton collision data collected by the ATLAS detector at the LHC in 2015–2018 at a centre-of-mass energy of 13 TeV. Dedicated techniques were developed for the reconstruction of displaced jets produced by LLPs decaying hadronic...

A bstract Cross-section measurements of top-quark pair production where the hadronically decaying top quark has transverse momentum greater than 355 GeV and the other top quark decays into ℓνb are presented using 139 fb − 1 of data collected by the ATLAS experiment during proton-proton collisions at the LHC. The fiducial cross-section at $$ \sqrt{s...

A bstract The associated production of a Higgs boson and a top-quark pair is measured in events characterised by the presence of one or two electrons or muons. The Higgs boson decay into a b -quark pair is used. The analysed data, corresponding to an integrated luminosity of 139 fb − 1 , were collected in proton-proton collisions at the Large Hadro...

A search is made for a vectorlike T quark decaying into a Higgs boson and a top quark in 13 TeV proton-proton collisions using the ATLAS detector at the Large Hadron Collider with a data sample corresponding to an integrated luminosity of 139 fb−1. The Higgs-boson and top-quark candidates are identified in the all-hadronic decay mode, where H→bb¯ a...

This paper reports constraints on Higgs boson production with transverse momentum above 1 TeV. The analyzed data from proton–proton collisions at a center-of-mass energy of 13 TeV were recorded with the ATLAS detector at the Large Hadron Collider from 2015 to 2018 and correspond to an integrated luminosity of 136 fb−1. Higgs bosons decaying into bb...

A search for resonant Higgs boson pair production in the bb¯bb¯ final state is presented. The analysis uses 126 fb−1–139 fb−1 of pp collision data at s=13 TeV collected with the ATLAS detector at the Large Hadron Collider. The analysis is divided into two channels, targeting Higgs boson decays which are reconstructed as pairs of small-radius jets o...

This paper presents an analysis at next-to-next-to-leading order in the theory of quantum chromodynamics for the determination of a new set of proton parton distribution functions using diverse measurements in pp collisions at s=7, 8 and 13 TeV, performed by the ATLAS experiment at the Large Hadron Collider, together with deep inelastic scattering...

This paper presents an analysis at next-to-next-to-leading order in the theory of quantum chromodynamics for the determination of a new set of proton parton distribution functions using diverse measurements in pp collisions at s√=7, 8 and 13 TeV, performed by the ATLAS experiment at the Large Hadron Collider, together with deep inelastic scattering...

A measurement of the energy asymmetry in jet-associated top-quark pair production is presented using $$139\,{\mathrm {fb}}^{-1}$$ 139 fb - 1 of data collected by the ATLAS detector at the Large Hadron Collider during pp collisions at $$\sqrt{s}=13\,\text {TeV}$$ s = 13 TeV . The observable measures the different probability of top and antitop quark...

A search is presented for the production of a single top quark via left-handed flavour-changing neutral-current (FCNC) interactions of a top quark, a gluon and an up or charm quark. Two production processes are considered: u+g→t and c+g→t. The analysis is based on proton–proton collision data taken at a centre-of-mass energy of 13 TeV with the ATLA...

Heavy-flavour hadron production provides information about the transport properties and microscopic structure of the quark–gluon plasma created in ultra-relativistic heavy-ion collisions. A measurement of the muons from semileptonic decays of charm and bottom hadrons produced in Pb+Pb and pp collisions at a nucleon–nucleon centre-of-mass energy of...

A search for invisible decays of the Higgs boson as well as searches for dark matter candidates, produced together with a leptonically decaying Z boson, are presented. The analysis is performed using proton−proton collisions at a centre-of-mass energy of 13 TeV, delivered by the LHC, corresponding to an integrated luminosity of 139 fb−1 and recorde...

This search, a type not previously performed at ATLAS, uses a comparison of the production cross sections for e+μ− and e−μ+ pairs to constrain physics processes beyond the Standard Model. It uses 139fb−1 of proton–proton collision data recorded at s=13 TeV at the LHC. Targeting sources of new physics which prefer final states containing e+μ− to e−μ...

A measurement of the energy asymmetry in jet-associated top-quark pair production is presented using 139fb-1 of data collected by the ATLAS detector at the Large Hadron Collider during pp collisions at s=13TeV. The observable measures the different probability of top and antitop quarks to have the higher energy as a function of the jet scattering a...

The ATLAS experiment at the Large Hadron Collider has a broad physics programme ranging from precision measurements to direct searches for new particles and new interactions, requiring ever larger and ever more accurate datasets of simulated Monte Carlo events. Detector simulation with Geant4 is accurate but requires significant CPU resources. Over...

The ATLAS experiment at the Large Hadron Collider has a broad physics programme ranging from precision measurements to direct searches for new particles and new interactions, requiring ever larger and ever more accurate datasets of simulated Monte Carlo events. Detector simulation with GEANT4 is accurate but requires significant CPU resources. Over...

The design and performance of the inner detector trigger for the high level trigger of the ATLAS experiment at the Large Hadron Collider during the 2016–2018 data taking period is discussed. In 2016, 2017, and 2018 the ATLAS detector recorded $$35.6~\mathrm {fb}^{-1}$$ 35.6 fb - 1 , $$46.9~\mathrm {fb}^{-1}$$ 46.9 fb - 1 , and $$60.6~\mathrm {fb}^{...

Searches are conducted for new spin-0 or spin-1 bosons using events where a Higgs boson with mass 125 GeV decays into four leptons (ℓ = e, μ). This decay is presumed to occur via an intermediate state which contains two on-shell, promptly decaying bosons: H → XX/ZX → 4ℓ, where the new boson X has a mass between 1 and 60 GeV. The search uses pp coll...

Searches are conducted for new spin-0 or spin-1 bosons using events where a Higgs boson with mass 125 GeV decays into four leptons (ℓ = e, μ). This decay is presumed to occur via an intermediate state which contains two on-shell, promptly decaying bosons: H → XX/ZX → 4ℓ, where the new boson X has a mass between 1 and 60 GeV. The search uses pp coll...

The design and performance of the inner detector trigger for the high level trigger of the ATLAS experiment at the Large Hadron Collider during the 2016–2018 data taking period is discussed. In 2016, 2017, and 2018 the ATLAS detector recorded 35.6 fb−1, 46.9 fb−1, and 60.6 fb−1 respectively of proton–proton collision data at a centre-of-mass energy...

This paper presents a measurement of the electroweak production of two jets in association with a Zγ pair, with the Z boson decaying into two neutrinos. It also presents a search for invisible or partially invisible decays of a Higgs boson with a mass of 125 GeV produced through vector-boson fusion with a photon in the final state. These results us...

This paper presents a measurement of the electroweak production of two jets in association with a Zγ pair, with the Z boson decaying into two neutrinos. It also presents a search for invisible or partially invisible decays of a Higgs boson with a mass of 125 GeV produced through vector-boson fusion with a photon in the final state. These results us...

The accurate simulation of additional interactions at the ATLAS experiment for the analysis of proton–proton collisions delivered by the Large Hadron Collider presents a significant challenge to the computing resources. During the LHC Run 2 (2015–2018), there were up to 70 inelastic interactions per bunch crossing, which need to be accounted for in...

The accurate simulation of additional interactions at the ATLAS experiment for the analysis of proton–proton collisions delivered by the Large Hadron Collider presents a significant challenge to the computing resources. During the LHC Run 2 (2015–2018), there were up to 70 inelastic interactions per bunch crossing, which need to be accounted for in...

This paper presents a search for decays of the Higgs boson with a mass of 125 GeV into a pair of new pseudoscalar particles, H→aa, where one a-boson decays into a b-quark pair and the other into a muon pair. The search uses 139 fb−1 of proton-proton collision data at a center-of-mass energy of s=13 TeV recorded between 2015 and 2018 by the ATLAS ex...