Conveners
Higgs & Electroweak Physics: HIG 1L
- Evelyn Jean Thomson (University of Pennsylvania (US))
- Laura Reina (Florida State University (US))
Higgs & Electroweak Physics: HIG 1B
- Nicholas Bower (Florida State University (US))
- Nan Lu (California Institute of Technology (US))
Higgs & Electroweak Physics: HIG 2B
- Robin Erbacher (University of California Davis (US))
- Laura Reina (Florida State University (US))
- Nan Lu (California Institute of Technology (US))
Higgs & Electroweak Physics: HIG 3B
- Nan Lu (California Institute of Technology (US))
- Tania Natalie Robens (Rudjer Boskovic Institute (HR))
Higgs & Electroweak Physics: HIG 4B
- Manfred Paulini (Carnegie-Mellon University (US))
- Manfred Kraus (Florida State University)
Higgs & Electroweak Physics: HIG 5B
- Xiangyang Ju (Lawrence Berkeley National Lab. (US))
- Nathaniel Craig (UC Santa Barbara)
Higgs & Electroweak Physics: HIG 6B
- Xiangyang Ju (Lawrence Berkeley National Lab. (US))
- Manfred Paulini (Carnegie-Mellon University (US))
Experimentally probing the charm-Yukawa coupling in the LHC experiments
is important, but very challenging due to an enormous QCD background. We study a new channel that can be used to search for the Higgs decay $H\to c\bar c$, using the vector boson fusion (VBF) mechanism with an associated photon. In addition to suppressing the QCD background, the photon gives an effective trigger handle....
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}=$13 TeV collected by the ATLAS experiment. Cross-sections for gluon fusion, weak vector boson fusion, associated production with a $W$ or $Z$ boson, and top quark associated production processes are reported. An upper limit of eight times...
The precision measurements of the properties of the Higgs boson are among the principal goals of the LHC Run-2 program. This talk reports on the measurements of the fiducial and differential Higgs boson production cross sections via Vector Boson Fusion with a muon, an electron, and two neutrinos from the decay of W bosons, along with the presence of two energetic jets in the final state. The...
The measurements at the Large Hadron Collider(LHC), so far, have established Higgs Yukawa couplings to Fermions are close to the Standard Model(SM) expectation for the 3rd Fermion generation. However, the rather ad hoc assumption of universal Yukawa coupling for other Fermion generations has a little experimental constraint. This is very challenging to probe due to small branching fractions,...
The dimuon decay of the Higgs boson is the most promising process for probing the Yukawa couplings to the second generation fermions at the Large Hadron Collider (LHC). We present a search for this important process using the data corresponding to an integrated luminosity of 139 fb$^{-1}$ collected with the ATLAS detector in $pp$ collisions at $\sqrt{s} = 13 \mathrm{TeV}$ at the LHC. Events...
The Large Hadron Collider (LHC) is a “top quark factory”. It allows for precise measurements of several top quark properties. In addition to this, for the first time ever it is now possible to measure rare processes involving top quarks. Associated production of top and anti-top quarks along with the Higgs boson or with electro-weak gauge bosons like W or Z has been observed at the LHC....
Following the discovery of the Higg's boson in 2012 by both the ATLAS and CMS experiments, a wealth of papers have been published concerning measurements or observations of the Higgs' decay modes. However, the most dominant decay mode, $H \rightarrow b\bar{b}$, proved to be an elusive and challenging search due to the low signal-to-background environment, and a diverse range of backgrounds...
The Higgs Boson is expected to decay to bb approximately 58% of the time. Despite the large branching fraction, due to the large background from Standard Model events with b-jets, measuring this decay has been less precise than other, less frequent, decays. Measuring H(bb) in the vector boson fusion production mode has historically been insensitive, but developments in the background estimates...
In this talk I will present results of the simulation of electroweak Higgs boson production at the CERN LHC using the Herwig 7 general purpose event generator using one-loop matrix elements via the interface to HJets. The main result will be the simulation of next-to-leading order merging of Higgs boson plus 2 and 3 jets with a dipole parton shower. Additionally, I will comment on...
The ever-growing interest into high-energy production of the Higgs boson, motivated by an enhanced sensitivity to New Physics scenarios, pushes the development of experimental techniques for the reconstruction of boosted decay products from the Higgs-boson hadronic decays.
This talk will discuss recent studies of inclusive Higgs-boson production with sizable transverse momentum decaying to a...
A search for the Standard Model Higgs boson produced in association with a high-energy photon is performed using ${132}$ ${fb^{-1}}$ of $pp$ collision data at $\sqrt{s}={13}$ TeV collected with the ATLAS detector at the Large Hadron Collider. The vector boson fusion production mode of the Higgs boson is particularly powerful for studying the $H(\rightarrow b \bar{b})\gamma$ final state because...
With the standard model working well in describing the collider data, the focus is now on determining the standard model parameters as well as for any hint of deviation. In particular, the determination of the couplings of the Higgs boson with itself and with other particles of the model is important to better understand the electroweak symmetry breaking sector of the model. In this
letter,...
A search for resonant Higgs boson pair production in the four b-jet final state is conducted. The analysis uses 36 fb$^{-1}$ of pp collision data at $\sqrt{s}$ = 13 TeV collected with the ATLAS detector. The analysis is divided into two regimes, targeting Higgs boson decays which are reconstructed as pairs of b-tagged small-radius jets or as single large-radius jets associated with b-tagged...
We present a search for non-resonant di-Higgs production in the $HH\rightarrow b\bar{b}\gamma\gamma$ decay channel. The measurement uses 139 $\mathrm{fb}^{-1}$ of pp collisions recorded by the ATLAS experiment at a center-of-mass energy of 13 TeV. Selected events are separated into multiple regions, targeting both the Standard Model (SM) signal and Beyond Standard Model (BSM) signals with...
After the Higgs Boson, with a mass of 125 GeV, was discovered in 2012, studies of single Higgs boson production have largely confirmed that this particle has similar properties to the Higgs boson predicted by the Standard Model (SM). However, it is clear that physics beyond the SM is required to explain many observed phenomena in nature, and there remains the possibility that the Higgs Boson...
Precision measurements of Higgs boson couplings to SM particles is a central task at the LHC today and for the future HL-LHC. Due to the $\sim$ O(nb) $t\bar{t}$ cross section and large Yukawa coupling, measurements of the interaction of the Higgs with top quarks is particularly compelling. The $t\bar{t}HH$ signal can be used to probe this coupling and also provides a direct measurement of...
A search for Higgs boson pair production in bbll+MET final state with the ATLAS experiment will be presented. The analysis uses the full Run~2 data-set (139fb−1) collected at the LHC in pp collisions at √s=13TeV. Di-Higgs boson production from the SM tri-Higgs-boson interaction and from BSM resonant decays are investigated with a final state containing two jets (one or two tagged as b-jets)...
Higgs boson pair production (HH) is one of the more interesting processes to study at the LHC, as it allows us to probe Higgs Boson self-coupling and associated parameters of the Higgs potential, as well as search for physics beyond the standard model. The $b\bar{b}\tau\tau$ final state is one of the most sensitive channels for HH studies due to an appreciable branching ratio, and a relatively...
A direct measurement of the Higgs self coupling is very crucial to understand the nature of electroweak symmetry breaking. This requires an observation of production of Higgs boson pair, which suffers from very low event rate even at the current LHC run. In our work, we study the prospects of observing the Higgs pair production at the high luminosity run of the 14 TeV LHC (HL-LHC) and also...
In this talk we will discuss the production of three Higgs bosons in the LHC and at a proton-proton collider running at a centre-of-mass energy of 100 TeV. We will argue that the seemingly challenging 6-botton jets final state is a very good candidate to investigate triple Higgs production within and beyond the SM in proton-proton colliders. In particular we will consider three different...
One of the assumptions of simplified models is that there are a few new particles and interactions accessible at the LHC and all other new particles are heavy and decoupled. The effective field theory (EFT) method provides a consistent method to test this assumption. Simplified models can be augmented with higher order operators involving the new particles accessible at the LHC. Any UV...
An Effective Field Theory (EFT) re-interpretation of the differential measurement of Vector Boson Fusion Higgs production and decay to two W bosons will be reported. The analysis used the full Run-2 data in 2015--2018 of $pp$ collisions at $\sqrt{s}$=13 TeV with the ATLAS detector at the LHC, which correspond to an integrated luminosity of 139 fb$^{−1}$. Events with an electron and a muon from...
Rare decays of the Higgs boson are promising laboratories to search for physics beyond the standard model (BSM). Such BSM physics might alter Yukawa couplings to lighter quarks and add loop diagrams, possibly resulting in higher decay rates than predicted by the standard model. For the first time in four-lepton final states, decays of the Higgs boson into a $ZJ/\psi$ or $Z\psi(2S)$ final...
Studies of CP violation and anomalous couplings of the Higgs boson to vector bosons and fermions are presented. The data were acquired by the CMS experiment at the LHC and correspond to an integrated luminosity of 137 fb−1 at a proton-proton collision energy of 13 TeV. The kinematic effects in the Higgs boson's four-lepton decay H → 4ℓ and its production in association with two jets, a vector...
The quest for lepton-flavor-violating processes at the LHC represents one of the key searches for new physics beyond the Standard Model (SM). We present a search for Higgs boson decays into a tau lepton and either an electron or a muon. The analysis uses data from proton-proton collisions at the LHC at $\sqrt{s}= 13$ TeV, collected by the ATLAS detector and corresponding to an integrated...
We explore the new physics reach for the off-shell Higgs boson measurement in the $pp \rightarrow 𝐻^∗ \rightarrow 𝑍(ℓ^+ℓ^−)𝑍(𝜈\bar{𝜈})$ channel at the high-luminosity LHC. The new physics sensitivity is parametrized in terms of the Higgs boson width, effective field theory framework, and a non-local Higgs-top coupling form factor. Adopting Machine-learning techniques, we demonstrate that the...
The top-quark Yukawa coupling $y_t$ is the strongest interaction of the Higgs boson in the Standard Model (SM) with $y_t \sim 1$. Due to its magnitude, it plays a central role in Higgs phenomenology in the SM and would be most sensitive to physics beyond the Standard Model. The top Yukawa can be directly measured at the LHC via top pair production in association with a Higgs boson...
We explore the direct Higgs-top CP structure via the $pp \to t\bar{t}h$ channel with machine learning techniques, considering the clean $h \to \gamma\gamma$ final state at the high luminosity LHC~(HL-LHC). We show that a combination of a comprehensive set of observables, that include the $t\bar{t}$ spin-correlations, with mass minimization strategies to reconstruct the $t\bar{t}$ rest frame...
The LHC is exploring electroweak (EW) physics at the scale EW symmetry is broken. As the LHC and new high energy colliders push our understanding of the Standard Model to ever-higher energies, it will be possible to probe not only the breaking of but also the restoration of EW symmetry. We propose to observe EW restoration in double EW boson production via the convergence of the Goldstone...
Triple gauge boson production is an important class of processes at the LHC. It allows measurements to test the quartic gauge couplings in the Standard Model and constrain the non-standard gauge couplings in the Standard Model effective field theory (SMEFT). We perform the computations of the NLO EW and QCD corrections to $W^{+}Z\gamma$ production with leptonic decays in SM at the LHC. The...
Precision measurements and searches for new phenomena in the Higgs sector are among the most important goals in particle physics. Experiments at the Future Circular Colliders (FCC) are ideal to study these questions. Electron-positron collisions (FCC-ee) up to an energy of 365 GeV provide the ultimate precision with studies of Higgs boson couplings, mass, total width, and CP parameters, as...
After the triumph of discovering the Higgs boson at the CERN Large Hadron Collider, people are getting increasingly interested in studying the Higgs properties in detail and searching for the physics beyond the Standard Model (SM). A multi-TeV lepton collider provides a clean experimental environment for both the Higgs precision measurements and the discovery of new particles. In high-energy...
The recently proposed MUonE experiment at CERN aims at providing a novel determination of the leading order hadronic contribution to the muon anomalous magnetic moment through the study of elastic muon-electron scattering at relatively small momentum transfer. The anticipated accuracy of the order of 10ppm requires high-precision predictions, including all the relevant radiative corrections....
We study electroweak phase transition and resultant GWs of a CP conserving 2HDM with a softly broken $Z_2$ symmetry. We analysed the parameter space of both type I and type II 2hdm without relying on any decoupling limit. We observe $M_{H^\pm} \approx M_H$ or $M_{H^\pm} \approx M_A$ favours SFOEWPT in 2HDM. In addition to di-Higgs production, scalar to fermion decay channel is also important...
A common assumption about the early universe is that it underwent an electroweak phase transition (EWPT). Though the standard model (SM) is able to restore the electroweak symmetry through a smooth cross over PT, we require a strongly first-order PT to ensure electroweak baryogenesis, requiring us to look at new physics beyond the SM. The simplest case to extend the SM is to add a real singlet...
What happens when we collide light at the highest laboratory energies? LHC beams source energetic photons that can collide to create new particles. Recently, ATLAS reported the landmark observation of photon-induced W boson pairs in the electron–muon channel using 139 fb$^{−1}$ of $\sqrt{s}$ = 13 TeV proton–proton collision data. A hallmark of photon fusion production is the forward scattering...
The search for the electroweak VBS production of a VW pair plus two jets in the semi-leptonic final state is presented. The full CMS dataset (137.1 fb-1) for the LHC Run II of proton-proton collisions at a center-of-mass energy of 13 TeV is analyzed. In the final state, we expect two well-separated jets with a high invariant mass, one lepton from the W boson decay, and the decay products of...
Identifying $𝑊𝑊^{(\ast)}\rightarrow\ell\nu qq$ from heavy particle decays at the LHC is an important but challenging problem due to overlapping lepton and jet signatures. We have developed a deep learning-based $𝑊𝑊^{(\ast)}$ tagger which learns from simulated calorimeter features to identify boosted $𝑊𝑊^{(\ast)}$ decays to semileptonic final states from $t\bar{t}$ and di-jet backgrounds in...
The Drell-Yan process is studied in the framework of TMD factorization in the Sudakov region $s\gg Q^2\gg q_\perp^2$
corresponding to recent LHC experiments with $Q^2$ of order of mass of Z-boson and transverse momentum
of DY pair $\sim$ few tens GeV. The DY hadronic tensors are expressed in terms of quark and quark-gluon TMDs
with ${1\over Q^2}$ and ${1\over N_c^2}$ accuracy.
It is...
We propose that the dynamics of a scalar $\phi$ of mass $O(10)$ MeV, weakly coupled to the Higgs, can give rise to a first order electroweak phase transition. Vacuum stability close to the weak scale requires a suppressed (maybe vanishing) top Yukawa coupling before the transition, rising to the Standard Model (SM) value later. All SM flavor could appear similarly, after the electroweak phase...
The measurement of the production of a $W$ boson with a $c$ quark (termed ''$W + c$ analysis'') is studied with the ATLAS detector using the full Run 2 dataset of $pp$ collisions at $\sqrt{s} = 13 \; \mathrm{TeV}$. This measurement is crucial in obtaining increasingly precise values of the $s$ and $\bar{s}$ parton distribution function (PDF) of the proton, as well as studying the physics of...
A study of optimization of signal sensitivity in the search for the Di-Higgs event in the ATLAS experiment is presented where one of the Higgs bosons decays via the $H \xrightarrow{} b\Bar{b}$ channel and the other via $H \xrightarrow{} WW^{*}$ with $b\Bar{b}l\nu qq$ as the final state. Large irreducible background contamination from $t\Bar{t}$ decay significantly decreases the signal...
