Higgs 2021

18 Oct 2021, 08:00 → 22 Oct 2021, 16:50 America/New_York

Giacinto Piacquadio (State University of New York (US))

We would like to thank all participants of Higgs 2021 for making this a successful workshop!

Awarded best parallel presentations 

Please have a look at the slides and video recordings of the seven selected best parallel presentations (alphabetical order):

• “Machine Learning the Higgs-top CP Measurement” Rahool Barman (Oklahoma State University) [video/slides/contribution]
• “Search for Higgs Boson Pair Production in the bbτ+ τ− Final State with the ATLAS Detector” Christopher Deutsch (University of Bonn) [video/slides/contribution]
• “Catching Heavy Vector Triplets with the SMEFT: from one-loop matching to phenomenology” Emma Geoffray (Universität Heidelberg) [video/slides/contribution]
• “Measurements and Interpretations of STXS and Differential and Fiducial Cross Sections in Higgs Boson Decays to two W Bosons with the ATLAS Detector” Robin Hayes (University of British Columbia) [video/slides/contribution]
• “Precision Higgs Physics at High-Energy Muon Colliders” Samuel Homiller (Harvard University) [video/slides/contribution]
• “Searches for resonant and non-resonant HH/YH production in final states with tau leptons and W bosons at CMS” Jona Motta (LLR, École Polytechnique) [video/slides/discussion slides/contribution]
• “Off-shell Higgs Couplings in 𝐻∗→𝑍𝑍→ℓℓ𝜈𝜈” Han Qin (University of Pittsburgh) [video/slides/contribution]

 

 

 

Higgs 2021 is this year's installment of an annual conference devoted to new experimental and theoretical results on the Higgs boson. The 2021 conference will present the latest results from the LHC on the Higgs boson mass, spin/parity, and couplings and will present new theoretical work devoted to the measurement of Higgs parameters and possibilities for exotic Higgs decays. The conference will provide an opportunity for critical discussion of the current strategies for studying the Higgs boson at the LHC and the next steps beyond the LHC. Higgs 2021 will include several sessions of parallel and plenary contributions on current research topics.

Update Sep 9th: 

The in-person component of the Higgs 2021 conference has been cancelled. The conference will be held virtually. This decision is driven not only by US-wide travel restrictions (from other countries), but also by self-imposed travel restrictions by DOE, DOE labs and several US institutions which make it impossible also for most US-based participants and speakers to travel to Stony Brook.

If you have any questions, you can reach the conference administrators at higgs2021-admins@cern.ch, and the full local organizing committee at higgs-couplings-Higgs2021-LOC@cern.ch. If you have any questions related to the program, please also add the program committee in cc: higgs-couplings-Higgs2021-PC@cern.ch.

 

Original Conference Venue (now only virtual!)

Stony Brook University
Simons Center for Geometry and Physics
John S. Toll Drive
Stony Brook, NY 11790 USA

Host

• Stony Brook University, Simons Center for Geometry and Physics

Sponsors and/or Co-sponsors

• Brookhaven National Laboratory

PC (Program Committee) members:

• Viviana Cavaliere (BNL)
• Karsten Köneke (Freiburg) - Chair
• Patrick Meade (YITP)
• Christopher Palmer (Princeton)
• Stefano Pozzorini (Zürich)
• Roberto Salerno (LLR)

Session conveners:

• Precision & Properties: Alexander Huss,  Hongtao Yang, David Sperka

• Yukawa: Patrick Meade, Nicolas Morange, Stephane Cooperstein 

• HH: Daniel Egana,  Liza Brost, Agni Bethani

• EFT: Tim Cohen, Nicolas Berger, Andrei Gritsan

• BSM: Zhen Liu, Verena Outschoorn, Luca Cadamuro 

• Snowmass/Future colliders: Sally Dawson, Caterina Vernieri,  Isobel Ojalvo
   

IOC members:

• Fabrizio Caola (Durham)
• Maria Cepeda Hermida (Ciemat)
• Michael Duehrssen (CERN)
• Keisuke Fujii (KEK)
• Gudrun Heinrich (KIT)
• Aneesh Manohar (UCSD)
• Giovanni Petrucciani (CERN)
• Giacinto Piacquadio (Stony Brook)
• Stefano Pozzorini (Zürich)
• Roberto Salerno (LLR)
• Kerstin Tackmann (DESY)
• James Wells (Michigan)
• Michael Williams (MIT)
   

LOC members:

• Haider Abidi (BNL)
• Luis Álvarez Gaumé (SCGP/YITP)
• Elizabeth Brost (BNL)
• Quentin Buat (SBU/UW)
• Viviana Cavaliere (BNL)
• Gloria Clivilles-Ramos (SBU admin)
• Sally Dawson (BNL/YITP)
• Paul Grannis (SBU)
• Tracy Hillenbrand (SBU admin)
• John Hobbs (SBU)
• Ilaria Luise (SBU)
• Patrick Meade (YITP)
• Giacinto Piacquadio (SBU/Chair)
• Marc-André Pleier (BNL)
• Robert Shrock (YITP)
• George Sterman (YITP)
• Alessandro Tricoli (BNL)
• Dmitri Tsybychev (SBU)

Registration 

Higgs 2021: 18-22 October 2021

• There will be no fee for remote participants

 

                                          

HIGGS2021.pdf

Monday, 18 October

1 Welcome from Local Organizers and Program Committee

Speakers: Giacinto Piacquadio (State University of New York (US)), Karsten Koeneke (Albert Ludwigs Universitaet Freiburg (DE))

Introduction to Higgs 2021 - slides.pdf

Plenary: Opening

Plenary ZOOM Meeting: 995 3901 6069
Passcode: [please register to get this information]
Mattermost channel for discussion for plenary Young Scientist Fora (all days): https://mattermost.web.cern.ch/higgs2021/channels/plenary-ysf-all-days

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Mattermost channel for discussions for Tuesday plenary Properties and Precision sessions: https://mattermost.web.cern.ch/higgs2021/channels/plenary-tue-precision

Mattermost channel for discussions for Tuesday plenary Flavor session: https://mattermost.web.cern.ch/higgs2021/channels/plenary-tue-flavor

Mattermost channel for discussions for Wednesday plenary DiHiggs session: https://mattermost.web.cern.ch/higgs2021/channels/plenary-wed-dihiggs

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Mattermost channel for discussions for Thursday plenary Theory input and experimental tools session: https://mattermost.web.cern.ch/higgs2021/channels/plenary-thu-theoryexp-tools

Mattermost channel for discussions for Friday plenary Future and Closing session: https://mattermost.web.cern.ch/higgs2021/channels/plenary-fri

Convener: Viviana Cavaliere (Brookhaven National Lab)

Zoom

Mattermost discussion channels

• Friday Future and Closing (plenary)
• Monday Opening 1&2 (plenary)
• Thursday EFT (plenary)
• Thursday Theory input and experimental tools (plenary)
• Tuesday Flavor (plenary)
• Tuesday Properties and Precision (plenary)
• Wednesday BSM (plenary)
• Wednesday DiHiggs (plenary)
• Young Scientist Fora (all days, plenary)

2 “New Higgs results from ATLAS” (20+10)

Speaker: Marc Escalier (IJCLab-Orsay)

escalier_Higgs2021.pdf

Opening1TalkMarc.mp4

3 “New Higgs results from CMS” (20+10)

Speaker: Keti Kaadze (Kansas State University (US))

KetiKaadze_Higgs2021.pdf

Opening1TalkKeti.mp4

4 “Higgs physics in the precision era” (25+10)

Speakers: Gavin Salam (C), Gavin Salam (University of Oxford)

higgs-precision-era.pdf

Opening1TalkGavin.mp4

11:00 Coffee Break (30 min)

Plenary: Opening 2

Plenary ZOOM Meeting: 995 3901 6069
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Mattermost channel for discussions for Tuesday plenary Flavor session: https://mattermost.web.cern.ch/higgs2021/channels/plenary-tue-flavor

Mattermost channel for discussions for Wednesday plenary DiHiggs session: https://mattermost.web.cern.ch/higgs2021/channels/plenary-wed-dihiggs

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Convener: Maria Cepeda (CIEMAT)

Zoom

Mattermost discussion channels

• Friday Future and Closing (plenary)
• Monday Opening 1&2 (plenary)
• Thursday EFT (plenary)
• Thursday Theory input and experimental tools (plenary)
• Tuesday Flavor (plenary)
• Tuesday Properties and Precision (plenary)
• Wednesday BSM (plenary)
• Wednesday DiHiggs (plenary)
• Young Scientist Fora (all days, plenary)

5 “BSM Higgs theory overview” (25+10)

Speaker: Scott Thomas (Rutgers University)

Opening2TalkScott.mp4

6 ATLAS: Wildcard (15+5)

Speaker: Quentin Buat (University of Washington (US))

Opening2TalkQuentin.mp4

quentin_buat_higgs_2021.pdf

7 CMS: Wildcard (15+5)

Speaker: Nicholas Wardle (Imperial College (GB))

CMS_wildcard_Higgs2021_nwardle.pdf

Opening2TalkNick.mp4

Plenary: Young Scientist talks

Plenary ZOOM Meeting: 995 3901 6069
Passcode: [please register to get this information]
Mattermost channel for discussion for plenary Young Scientist Fora (all days): https://mattermost.web.cern.ch/higgs2021/channels/plenary-ysf-all-days

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Mattermost channel for discussions for Tuesday plenary Properties and Precision sessions: https://mattermost.web.cern.ch/higgs2021/channels/plenary-tue-precision

Mattermost channel for discussions for Tuesday plenary Flavor session: https://mattermost.web.cern.ch/higgs2021/channels/plenary-tue-flavor

Mattermost channel for discussions for Wednesday plenary DiHiggs session: https://mattermost.web.cern.ch/higgs2021/channels/plenary-wed-dihiggs

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Mattermost channel for discussions for Friday plenary Future and Closing session: https://mattermost.web.cern.ch/higgs2021/channels/plenary-fri

Convener: Marc-Andre Pleier (Brookhaven National Laboratory (US))

Zoom

Mattermost discussion channels

• Friday Future and Closing (plenary)
• Monday Opening 1&2 (plenary)
• Thursday EFT (plenary)
• Thursday Theory input and experimental tools (plenary)
• Tuesday Flavor (plenary)
• Tuesday Properties and Precision (plenary)
• Wednesday BSM (plenary)
• Wednesday DiHiggs (plenary)
• Young Scientist Fora (all days, plenary)

8 More light on Higgs flavor at the LHC: Higgs couplings to light quarks through h+γ production

Higgs production in association with a photon at hadron colliders is a rare process, not yet observed at the LHC. We show that this process is sensitive to significant deviations of Higgs couplings to first and second generation SM quarks (particularly the up-type) from their SM values, and use a multivariate neural network analysis to derive the prospects of the High Luminosity LHC to probe deviations in the up and charm Higgs Yukawa couplings through h+γ production.

Speaker: Jose Manuel Cano (IFT UAM-CSIC)

JMCano_Higgs2021_slides.pdf

YSF1talk1.mp4

9 Fully differential Higgs production in VBF at NNLO, including the decay of the Higgs boson

I present new results for fully differential next-to-next-to-leading-order corrections to Higgs boson production in vector-boson fusion in the factorizing limit. In addition to previous computations the fully differential decay of the Higgs boson at leading order is included.

Speaker: Konstantin Asteriadis (Brookhaven National Laboratory)

asteriadis_higgs2021.pdf

YSF1talk2.mp4

13:15 Lunch Break

Time for watching pre-recorded videos of parallel sessions

Tuesday, 19 October

Time for watching pre-recorded videos of parallel sessions: (for people in Europe, Africa, Asia, Australia, etc)

Plenary: Properties and Precision

Plenary ZOOM Meeting: 995 3901 6069
Passcode: [please register to get this information]
Mattermost channel for discussion for plenary Young Scientist Fora (all days): https://mattermost.web.cern.ch/higgs2021/channels/plenary-ysf-all-days

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Mattermost channel for discussions for Tuesday plenary Properties and Precision sessions: https://mattermost.web.cern.ch/higgs2021/channels/plenary-tue-precision

Mattermost channel for discussions for Tuesday plenary Flavor session: https://mattermost.web.cern.ch/higgs2021/channels/plenary-tue-flavor

Mattermost channel for discussions for Wednesday plenary DiHiggs session: https://mattermost.web.cern.ch/higgs2021/channels/plenary-wed-dihiggs

Mattermost channel for discussions for Wednesday plenary BSM session: https://mattermost.web.cern.ch/higgs2021/channels/plenary-wed-bsm

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Mattermost channel for discussions for Friday plenary Future and Closing session: https://mattermost.web.cern.ch/higgs2021/channels/plenary-fri

Convener: Stefano Augusto Pozzorini (Universitaet Zuerich (CH))

Zoom

Mattermost discussion channels

• Friday Future and Closing (plenary)
• Monday Opening 1&2 (plenary)
• Thursday EFT (plenary)
• Thursday Theory input and experimental tools (plenary)
• Tuesday Flavor (plenary)
• Tuesday Properties and Precision (plenary)
• Wednesday BSM (plenary)
• Wednesday DiHiggs (plenary)
• Young Scientist Fora (all days, plenary)

10 ATLAS+CMS: “SM Higgs-boson properties: mass, width, CP” (20+10)

Speaker: Savvas Kyriacou (Johns Hopkins University (US))

GMT20211019-130238_Recording_1920x1080.mp4

Higgs2021_SavvasKyriacou.pdf

11 Recent progress in precision calculations” (20+10)

Speaker: Alexander Yohei Huss (CERN)

GMT20211019-133209_Recording_2560x1440.mp4

Higgs2021_Huss.pdf

12 ATLAS+CMS: “Higgs-boson differential, fiducial, and total cross section measurements” (20+10)

Speaker: Edward Scott (Imperial College (GB))

ES_Higgs2021_FiducialDifferential.pdf

GMT20211019-140441_Recording_1760x900.mp4

13 ATLAS+CMS: “Higgs-boson couplings and simplified template cross section measurements” (20+10)

Speaker: Rachel Jordan Hyneman (SLAC National Accelerator Laboratory (US))

GMT20211019-143128_Recording_2560x1440.mp4

higgs2021_final.pdf

11:00 Coffee Break

Plenary: Flavor

Plenary ZOOM Meeting: 995 3901 6069
Passcode: [please register to get this information]
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Convener: Patrick Meade (Stony Brook University)

Zoom

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• Friday Future and Closing (plenary)
• Monday Opening 1&2 (plenary)
• Thursday EFT (plenary)
• Thursday Theory input and experimental tools (plenary)
• Tuesday Flavor (plenary)
• Tuesday Properties and Precision (plenary)
• Wednesday BSM (plenary)
• Wednesday DiHiggs (plenary)
• Young Scientist Fora (all days, plenary)

14 ATLAS+CMS: “Quark Yukawa interactions” (20+10)

Speaker: Loukas Gouskos (CERN)

GMT20211019-153808_Recording_1760x900.mp4

lg-higgsyukawa-higgs2021_final.pdf

15 ATLAS+CMS: “Lepton Yukawa interactions” (20+10)

Speaker: Martina Laura Ojeda (Deutsches Elektronen-Synchrotron (DE))

GMT20211019-160205_Recording_1760x900.mp4

LeptonYukawaInteractions_Higgs2021.pdf

16 Higgs Flavor in light of anomalies” (20+10)

Speakers: Clara Murgui, Clara Murgui

GMT20211019-162837_Recording_2560x1440.mp4

Higgs2021v1.pdf

13:00 Lunch Break

Parallel: Di-Higgs: [Room A]

Parallel A ZOOM Meeting: 683 5990 0577
Passcode: [please register to get this info]

Mattermost channel for discussions: https://mattermost.web.cern.ch/higgs2021/channels/di-higgs

Conveners: Agni Bethani (Universite Catholique de Louvain (UCL) (BE)), Daniel Egana-Ugrinovic (Perimeter Institute), Elizabeth Brost (Brookhaven National Laboratory (US))

Mattermost discussion

Zoom link A

17 Complex Singlet Benchmarks

Introducing simplified models with new particles/symmetries is one of the simplest solutions to the questions unanswered by the Standard Model of particles physics. We explore the phenomenology of adding a complex scalar singlet to the Standard Model without imposing any additional symmetries. This extension is particularly interesting since the model has three scalar mass eigenstates. This allows the production of discalar resonances between two different mass states. Additionally, the model can produce decay chains with several scalar resonances and other unique collider signatures. We study several benchmark scenarios that highlight the importance of various thresholds and display the rich phenomenology of the complex singlet model. We consider constraints such as narrow width, boundedness, perturbative unitarity, Higgs fits, and direct searches. We also compare the projected constraints for future colliders experiments such as the High Luminosity Large Hadron Collider, the International Linear Collider, and the Future Circular Colliders.

Speaker: Samuel Lane (University of Kansas)

lane_parallel.mp4

lane_parallel.pdf

18 Access to triple Higgs couplings in the 2HDM at future e+e- colliders

In this talk, we will analyze the production cross sections of two
neutral Higgs bosons in models with two Higgs doublets (2HDM) with
$CP$ conservation at future $e^{+}e^{-}$ colliders (specifically
ILC and CLIC). Based on a previous work, we have studied the two main
processes where the triple Higgs couplings can play an important role:
$e^{+}e^{-}\to h_{i}h_{j}\nu\bar{\nu}$ (mainly through vector boson
fusion) and $e^{+}e^{-}\to h_{i}h_{j}Z$ (similar to Higgs-strahlung)
with $h_{i}h_{j}=hh,\ hH,\ HH\ \text{or}\ AA$. The processes are
studied at all the foreseen center-of-mass energies and luminosities
of such future colliders. The results of the cross sections are presented
in benchmark planes where large triple Higgs couplings can be realized
inside the region allowed by all the relevant theoretical and experimental
constraints. We find large deviations from the SM in the production
of two SM-like Higgs bosons and sizable production cross sections
for $h_{i}h_{j}=hH$, $HH$ and \emph{$AA$ }in large parts of the
allowed parameter space. Furthermore, we explore the distributions
of the cross section with respect to the invariant mass of the final
Higgs pair. We analyze how these distributions can be used to disentangle
the resonant or non-resonant effects from the triple Higgs couplings.
We find sizable effects from $\lambda_{hhh}$, $\lambda_{hhH}$, $\lambda_{hHH}$
and $\lambda_{hAA}$, specially at large center-of-mass energies in
the $h_{i}h_{j}\nu\bar{\nu}$ production channel.

Speaker: Francisco Arco (IFT)

ArcoHiggs2021.mp4

ArcoHiggs2021.pdf

19 Probing di-Higgs using machine learning techniques

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 the proposed high energy upgrade of the LHC at 27 TeV, namely, HE-LHC. For the HL-LHC study, we choose multiple final states based on the event rate and cleanliness, namely, $b\bar{b}\gamma \gamma$, $b\bar{b} \tau^+ \tau^-$, $b\bar{b} WW^*$, $WW^*\gamma \gamma$ and $4W$ channels and do a collider study by employing a cut-based as well as multivariate analyses using the Boosted Decision Tree (BDT) algorithm. In case of HE-LHC study, we select various di-Higgs final states based on their cleanliness and production rates, namely, $b\bar{b}\gamma\gamma$, $b\bar{b}\tau^{+}\tau^{-}$, $b\bar{b}WW^{*}$, $WW^{*}\gamma\gamma$, $b\bar{b}ZZ^{*}$ and $b\bar{b}\mu^{+}\mu^{-}$ channels. We adopt multivariate analyses using BDT algorithm, the XGBoost toolkit and Deep Neural Network (DNN) for the signal-background discrimination. Also, we perform a study on the ramifications of varying the self-coupling of Higgs boson from its Standard Model (SM) value.

Speaker: Dr Amit Adhikary (Centre for High Energy Physics, Indian Institute of Science, Bangalore 560012, India)

Higgs2021_AmitAdhikary.pdf

Recording_Higgs2021.mov

20 Search for Higgs boson pair production in the bbtautau final state with the ATLAS detector

The discovery of the Higgs boson and the measurement of its properties confirming the Standard Model (SM) is a major step towards the understanding of electroweak symmetry breaking. As a result, the potential of the Higgs field, and therefore the self-coupling of the Higgs boson, is precisely predicted in the SM. It can be probed by measuring the cross section of Higgs boson pair production, offering an additional test of the SM. In the SM such measurements are difficult due to the destructive interference of amplitudes containing the self-coupling and amplitudes only containing Yukawa couplings to top quarks, leading to a small production cross section at the Large Hadron Collider (LHC). An enhancement would indicate the presence of physics beyond the SM, for example due to scalar resonances decaying into pairs of Higgs bosons. A search for non-resonant and resonant Higgs boson pair production in events with two b-jets and two tau-leptons is presented. It is performed using 139/fb of pp collision data recorded at sqrt(s) = 13 TeV by the ATLAS experiment during Run 2 of the LHC. The analysis considers semi-leptonic and fully hadronic di-tau final states and aims to set upper limits on the production cross section of Higgs boson pairs in the SM as well as on the resonant production of narrow-width scalars with masses ranging from the Higgs pair production threshold up to 1.6 TeV.

Speaker: Christopher Deutsch (University of Bonn (DE))

2021_10_19_higgs21_cdeutsch.mp4

2021_10_19_higgs21_cdeutsch.pdf

21 Searches for Higgs boson pair production with the full LHC Run 2 dataset in ATLAS

The latest results on the production of Higgs boson pairs (HH) in the ATLAS experiment are reported, with emphasis on searches based on the full LHC Run 2 dataset at 13 TeV. In the case of non-resonant HH searches, results are interpreted both in terms of sensitivity to the Standard Model and as limits on the Higgs boson self-coupling strength. Prospects of testing the Higgs boson self-coupling at the High Luminosity LHC (HL-LHC) will also be presented.

Speaker: Ivan Sayago Galvan (Univ. of Valencia and CSIC (ES))

Higgs2021_Searches_DiHiggs.mp4

Higgs2021_Searches_diHiggs.pdf

22 Searches for resonant and non-resonant HH/YH production in final states with tau leptons and W bosons at CMS

We present the latest results from the CMS Collaboration on searches for new resonances that decay into two scalar bosons as well as for non-resonant production of two 125 GeV Higgs bosons. The presented searches consider decays of at least one of the scalars into a W boson or tau lepton, leading to final states like bbtautau and bbWW, amongst others.
Files

Speaker: Jona Motta (LLR, École Polytechnique (FR))

discussion_starter_HH_YH_bbWW_bbtautau.pdf

presentation_HH_YH_bbWW_bbtautau.pdf

recording_HH_YH_bbWW_bbtautau.mp4

23 Search for non-resonant Higgs boson pair production in the bbyy final state at CMS

In this talk, the latest results from CMS for the search for non-resonant Higgs boson pair production in the final state with two b-quarks and two photons is presented. The analysis uses the full CMS Run 2 dataset and shows significant improvement from the previous CMS search, resulting in one of the most sensitive limits on non-resonant di-Higgs production at the LHC to date.

Speaker: Toyoko Orimoto (Northeastern University (US))

higgs2021_cms_hhbbgg_toyoko_orimoto_discussion.pdf

higgs2021_cms_hhbbgg_toyoko_orimoto.pdf

higgs2021_cms_hhbbgg_toyoko_orimoto_recording.mp4

24 Searches for resonant and non-resonant Higgs boson pair production in the four bottom quark final state at 13 TeV

This presentation will provide an overview of the latest results from the CMS collaboration on searches for resonant and non-resonant Higgs boson pair production decaying into four bottom quarks. The chosen final state guarantees the largest branching ratio. Presented results are extracted from the dataset of proton-proton collisions at 13 TeV of center-of-mass energy collected during the 2016-2018 Run-2 LHC data-taking period, which corresponds to 138 fb$^{-1}$ of integrated luminosity. Particular focus will be dedicated to the background model techniques crucial to properly model the large QCD background affecting the considered final state. These, together with the use of machine learning techniques allowed to boost the sensitivities yielding the current tightest constraint on the Higgs boson pair production cross section and to strongly constrain the presence of physics Beyond the Standard Model.

Speaker: Angela Taliercio (Universite Catholique de Louvain (UCL) (BE))

Higgs21_HH4b_ATaliercio.mp4

Higgs21_HH4b_Taliercio.pdf

25 New approaches for hh→bbbb as a probe of Higgs self-coupling

Abstract:
Searches for pairs of Higgs bosons will be, in all likelihood, the best tools to precisely measure the Higgs boson self-coupling $\lambda_{hhh}$ in future colliders. We study various strategies for the $hh\to b \bar{b} b \bar{b}$ search in the HL-LHC era with focus on constraining $\lambda_{hhh}$. We implement a machine-learning-based approach to separate signal and background and apply recent advances in machine learning interpretability, compare the traditional 4 $b$-jet reconstruction to final states with 1 or 2 large-radius jets, and test scenarios with different top-quark Yukawa couplings, among other factors.
Based on arXiv:2004.04240.

Speaker: Santiago Rafael Paredes Saenz (Universite Libre de Bruxelles (BE))

sps_higgs2021_hh4b.mp4

sps_higgs_hh4b.pdf

Parallel: EFT: [Room C]

Parallel C ZOOM Meeting: 617 4486 8526
Passcode: [please register to get this info]

Mattermost channel for discussions: https://mattermost.web.cern.ch/higgs2021/channels/eft

Conveners: Andrei Gritsan (Johns Hopkins University (US)), Nicolas Berger (Centre National de la Recherche Scientifique (FR)), Tim Cohen (University of Oregon)

Mattermost discussion

Zoom link C

26 CP-Violating Invariants in the SMEFT

In the Standard Model, CP violation in the Electroweak sector is parametrized by the Jarlskog Invariant. This is the flavor invariant sensitive to CP violation with the least number of Yukawa matrices that can be built. When higher dimensional operators are allowed, and the Standard Model Effective Field Theory is constructed, numerous new sources for CP violation can appear. However, the description of CP violation as a collective effect, present in the SM, is inherited by its Effective extension. Here, I will discuss how such a behaviour can be consistently captured, at dimension 6, by flavor invariant, CP violating objects, linear in the Wilson coefficients. Such a description ensures that CP violation in the SMEFT is treated in a basis independent manner. In particular, I claim these are the objects that have to vanish, together with the SM Jarlskog Invariant, for CP to be conserved, and viceversa. The scaling properties of these invariants demonstrates that, while CP is not an accidental symmetry of the Standard Model, its breaking is accidentally small at the renormalizable level. Implications for specific flavor models, such as MFV, will be addressed.

Speaker: Emanuele Gendy Abd El Sayed (DESY)

Higgs.mp4

Higgs.pdf

27 The JHU generator framework: EFT applications in Higgs physics

The JHUGenerator framework includes an event generator of all anomalous Higgs boson interactions in both production and decay and the MELA library for matrix element analyses. The framework also allows using dimension-six operators of an EFT in on-shell and off-shell production together with triple and quartic gauge boson interactions. One new feature is the JHUGenLexicon interface for relating the anomalous coupling formulation with popular EFT bases. Some of the new features are illustrated along with projections for experimental measurements with the full LHC and HL-LHC datasets.

Speaker: Savvas Kyriacou (Johns Hopkins University (US))

HIGG2021_jhugen_Savvas.mp4

HIGGS2021_photons_SavvasKyriacou.pdf

28 Higgs CP and anomalous coupling measurements in the H->tautau and H->ZZ final states from CMS

The latest CMS measurements of the Higgs CP properties and anomalous couplings in the H->ZZ and H->tautau final states and their combination will be discussed.

Speaker: Daniel Winterbottom (Imperial College (GB))

Higgs2021.pdf

Higgs21_recording_v2.mp4

29 Effective Field Theory interpretations of ATLAS measurements

In the absence of direct observations of new physics beyond the Standard Model, interpretations of results using Effective Field Theories can be a powerful tool to place near-model-independent constraints on new physics scenarios, or better observe deviations from the Standard Model and have it interpreted in terms of specific new interactions. This talk presents Effective Field Theory interpretations of individual and combined results from the ATLAS experiment.

Speaker: Carsten Daniel Burgard (Deutsches Elektronen-Synchrotron (DE))

Q&A slides

slides.pdf

talk.mp4

30 A Simple Perturbative UV Completion of HEFT

Particles which acquire some fixed fraction of their mass from the Higgs are non-decoupling since their coupling to the Higgs grows in proportion to their mass. In particular, particles which acquire more than half of their mass from the Higgs, here termed Loryons, are appropriately described by HEFT rather than SMEFT. As such, BSM Loryons are a simple perturbative UV completion of HEFT which cannot be written as a convergent SMEFT. Unitarity constraints bound the size of the coupling and thus the mass of new Loryons to $\mathcal{O}(1)$ TeV, meaning that Loryons have a finite parameter space for experimental searches. We examine the bounds on possible new scalar and fermionic Loryons from direct searches and from indirect bounds through precision measurements. We find that a number of candidates remain viable and thus could be targets for future searches and that improved measurements of Higgs couplings would strongly constrain the viable parameter space.

Speaker: Ian Banta (University of California, Santa Barbara)

Ian_Banta_Higgs_2021.mp4

Ian_Banta_Higgs_2021.pdf

31 Catching Heavy Vector Triplets with the SMEFT: from one-loop matching to phenomenology

An important question for both phenomenologists and experimentalists is whether one can put limits on UV model parameters by matching the full theory onto the SMEFT. I will show that this is possible but the limits set through a SMEFT framework are weaker than they would be for the full model. This is because truncating the SMEFT Lagrangian at dimension six and matching to the full model introduces additional theoretical uncertainties.

I show that this impacts the limits set for the Heavy Vector Triplet extension of the Standard Model, one of the reasons being that the constraints now depend on the matching scale. I use the SFitter framework to derive limits taking into account Higgs measurements and electroweak precision data previously implemented. In addition, I discuss the impact of two new resonance searches for VH and VV on the fit.

Speaker: Emma Geoffray (Universität Heidelberg)

Geoffray_Higgs2021_Handout.pdf

Geoffray_Higgs2021_Video.mp4

32 Optimally sensitive observables for global EFT fits

Global interpretations of particle physics data in the context of the Standard Model Effective Field Theory (SMEFT) rely on the combination of a wide range of physical observables from many different processes. A key open question to inform such global SMEFT fits is how one can construct new classes of measurements that bring in, in a well-defined statistical sense, a maximal amount of information into the EFT parameter space. We present ongoing work towards assembling optimally-sensitive LHC observables for EFT fits based on unbinned deep-learning parametrisations of the extended log-likelihood ratio, with the ultimate goal of integrating such observables as building blocks of future global EFT fits. We validate them with explicit analytic calculations, and devote particular attention to the role played by systematic and theory errors. As a proof of concept, we study the constraints on the SMEFT parameter space provided by top quark pair production and by Higgs boson production in association with vector bosons at the HL-LHC. Furthermore, we study to what degree binned analyses can achieve sensitivity approaching the optimal limit.

Speaker: Jaco ter Hoeve (VU Amsterdam / Nikhef)

Higgs2021.mp4

slides_higgs21.pdf

33 Top, Higgs, Diboson and Electroweak Fit to the Standard Model Effective Field Theory

The search for effective field theory deformations of the Standard Model (SM) is a major goal of particle physics that can benefit from a global approach in the framework of the Standard Model Effective Field Theory (SMEFT). For the first time, we include LHC data on top production and differential distributions together with Higgs production and decay rates and Simplified Template Cross-Section (STXS) measurements in a global fit, as well as precision electroweak and diboson measurements from LEP and the LHC, in a global analysis with SMEFT operators of dimension 6 included linearly. We present the constraints on the coefficients of these operators, both individually and when marginalised, in flavour-universal and top-specific scenarios, studying the interplay of these datasets and the correlations they induce in the SMEFT. We then explore the constraints that our linear SMEFT analysis imposes on specific ultra-violet completions of the Standard Model, including those with single additional fields and low-mass stop squarks. We also present a model-independent search for deformations of the SM that contribute to between two and five SMEFT operator coefficients. In no case do we find any significant evidence for physics beyond the SM. Our underlying Fitmaker public code provides a framework for future generalisations of our analysis, including a quadratic treatment of dimension-6 operators.

Speaker: Ken Mimasu (King's College London)

Slides Mimasu_Higgs.pdf

Video MIMASU_HIGGS.mp4

34 Combined SMEFT interpretation of Higgs, diboson, and top quark data from the LHC

We present a global interpretation of Higgs, diboson, and top quark production and decay measurements from the LHC in the framework of the Standard Model Effective Field Theory (SMEFT) at dimension six. We constrain simultaneously 36 independent directions in its parameter space, and compare the outcome of the global analysis with that from individual and two-parameter fits. Our results are obtained by means of state-of-the-art theoretical calculations for the SM and the EFT cross-sections, and account for both linear and quadratic corrections in the $1/\Lambda^2$ expansion. We demonstrate how the inclusion of NLO QCD and $\mathcal{O}(Λ^{−4})$ effects is instrumental to accurately map the posterior distributions associated to the fitted Wilson coefficients. We assess the interplay and complementarity between the top quark, Higgs, and diboson measurements, deploy a variety of statistical estimators to quantify the impact of each dataset in the parameter space, and carry out fits in BSM-inspired scenarios such as the top-philic model. Our results represent a stepping stone in the ongoing program of model-independent searches at the LHC from precision measurements, and pave the way towards yet more global SMEFT interpretations extended to other high-pT processes as well as to low-energy observables.

Speakers: Giacomo Magni (Nikhef, VU Amsterdam), Juan Rojo (VU Amsterdam and Nikhef)

Slides_19_10_21.pdf

video1449955701.mp4

Parallel: Joint Future/BSM: Live discussion session 1 [Room B]

Parallel B ZOOM Meeting: 637 8781 0364
Passcode: [please register to get this info]

Mattermost channel for discussions: https://mattermost.web.cern.ch/higgs2021/channels/joint-futurebsm

Conveners: Caterina Vernieri (SLAC National Accelerator Laboratory (US)), Isobel Ojalvo (Princeton University (US)), Luca Cadamuro (University of Florida (US)), Sally Dawson (BNL), Verena Ingrid Martinez Outschoorn (University of Massachusetts (US)), Zhen Liu (University of Minnesota)

Mattermost discussion

Zoom link B

35 Precision Higgs Physics at High-Energy Muon Colliders

A high energy muon collider is an exciting option for exploring the energy frontier beyond the LHC. In addition to having a powerful energy reach, I will discuss how a multi-TeV muon collider also acts as a “vector-boson collider”, allowing for large rates of electroweak processes that can be leveraged for precision measurements of the Higgs sector, via both on- and off-shell measurements. I will also discuss how precision measurements of the Higgs at a muon collider can be used as a unique probe of beyond the Standard Model physics, with measurements complementary to other precision experimental programs.

Speaker: Samuel Homiller (Harvard University)

211019_higgs_at_mumu_homiller.mp4

211019_higgs_at_mumu_homiller.pdf

36 Precision Test of the Muon-Higgs Coupling at a High-energy Muon Collider

An open question in particle physics is whether the Higgs mechanism generates the masses of all the fermions by the Yukawa interactions. We propose to scrutinize the muon Yukawa coupling at a high-energy muon collider. By the subtle interplay between the muon Yukawa coupling in the high-energy production of multiple (vector and Higgs) bosons, we show that it is possible to measure the muon Yukawa coupling to an accuracy of ten percent for a 10 TeV collider and a few percent for a 30 TeV machine.

Speaker: Keping Xie (University of Pittsburgh)

GMT20211018-142702_Recording_as_1260x1006.mp4

Ymu_Xie.pdf

37 Search of Higgs exotic decays at the ILC

One important class of models of dark matter as a light fermionic weakly interaction massive particle (WIMP) couples the WIMP to a new singlet scalar field that mixes with the Higgs doublet.
The mixing couples the Higgs boson to a new scalar particle called the mediator φ. When the mixing angle is small, the mediator couples to the WIMP without any suppression while the coupling between the Higgs boson and WIMP is suppressed. In these models, the process h → φφ leads to invisible Higgs decays, but it also leads to new decay modes in which the mediator φ is directly visible, for example, through its decay φ→bb. A future lepton collider is expected to play an important role in the search for these new Higgs decay modes. In this talk we describe a full simulation study at the 250 GeV ILC based on the ILD detector concept. The signal production process is e+e− → Zh followed by exotic Higgs decays through h → φφ. We will focus on the decay channel φ→bb with a mediator mass from 15 GeV to 60 GeV and report the expected limit on the branching ratio of the exotic Higgs decay h→4b.

Speaker: Yu Kato (The University of Tokyo)

Higgs2021_YK_211019.mp4

Higgs2021_YK_211019.pdf

38 The THDMa and possible e+e- signatures

The THDMa is a new physics model that extends the scalar sector of the Standard Model by an additional doublet as well as a pseudoscalar singlet and allows for mixing between all possible scalar states. In the gauge eigenbasis, the additional pseudoscalar serves as a portal to the dark sector, with a priori any dark matter spin states. The option where dark matter is fermionic is currently one of the standard benchmarks for the experimental collaborations, and several searches at the LHC constrain the corresponding parameter space. However, most current studies constrain regions in parameter space by setting all but 2 of the 12 free parameters to fixed values.
I will discuss a generic scan on this model, allowing all parameters to float. All current theoretical and experimental constraints are applied. I identify regions in the parameter space which are still allowed after these have been applied and which might be interesting for an investigation at a future e+e- collider.

Speaker: Tania Natalie Robens (Rudjer Boskovic Institute (HR))

trobens.mp4

trobens.pdf

trobens_summ.pdf

39 The Running b quark mass in Higgs boson physics

The Standard Model prediction for the Higgs boson coupling to the b quark requires as input the running b quark mass evaluated at the scale of m_H. The running is large effect, reducing the prediction for the Yukawa coupling to 60% of the value that would be predicted from the nominal (PDG) value of the b quark mass. In this talk, we will discuss the theory uncertainties in the calculation of running of the b quark mass and the possibility of testing this theory at e+e- colliders with higher-precision measurements at the Z resonance and in Higgs and 4-fermion processes at 250 GeV. We present a measurement of the bottom quark mass at the scale of mH, extracted from ATLAS and CMS measurements of Higgs couplings, and the prospects for future improvements at the HL-LHC and a future Higgs factory.

Speaker: Javier Alberto Aparisi Pozo (Univ. of Valencia and CSIC (ES))

slides_bmass_talk_HIGGS21.pdf

video_bmass_talk_HIGGS21.mp4

40 Precision from Diboson Processes at FCC-hh

Thanks to its high luminosity and center of mass energy, the future FCC-hh collider will allow us to probe processes with clean but rare final states that are unaccessible at the LHC. The study of diboson production processes poses a promising way of indirectly constraining New Physics in the context of the Higgs Boson. Specifically, the diphoton leptonic decay channels of the Wh and Zh production processes are examples for the aforementioned clean but rare final states. I will discuss our study of these channels at the FCC-hh in the SMEFT framework and how doubly differential distributions can be used to gain even better sensitivity to certain higher dimensional EFT operators.

Speaker: Alejo Rossia (Deutsches Elektronen-Synchrotron DESY)

Rossia_Unveiling_Higgs_FCC-hh_Diboson.mp4

Rossia_Vh_Higgs_2021.pdf

Rossia_Vh_Higgs_2021_Summary.pdf

41 Higgs bosons signals of muon g-2 at the LHC and future colliders

Among the simplest new physics explanations of the muon g-2 anomaly are scenarios with additional contributions mediated by SM gauge or Higgs bosons and new leptons. The leptons can be very heavy, even beyond the reach of future colliders, and thus the confirmation of such explanations might rely only on indirect evidence. This includes modifications of muon couplings to $Z$, $W$ and Higgs bosons from SM predictions that can be searched for at the LHC and future colliders. Especially, a deviation of $h\to \mu^+ \mu^-$ from SM prediction would be highly suggestive of this explanation. In addition, I will discuss di-Higgs and tri-Higgs signals tightly related to the explanation of muon g-2. Due to large predicted rates, even a very low energy muon collider could see a signal or rule out these models.

Speaker: Radovan Dermisek

Dermisek_Higgs-eSBU&BNL-Oct_19_2021.mp4

Dermisek_Higgs-eSBU&BNL-Oct_19_2021.pdf

42 Vector boson fusion production of a single Higgs boson decaying to jets at a future muon collider

A multi-TeV muon collider provides a unique environment for future precision Higgs measurements, combining the lower backgrounds of lepton colliders with higher energy reach than achievable at an $e^+e^-$ collider. The large branching fraction of the Higgs boson to jets and lower hadronic backgrounds compared to $pp$ colliders potentially allows the channel to be a clean probe of the Higgs couplings to quarks and electroweak bosons. We study the possible sensitivity to this channel through the dominant vector boson fusion production mechanism.

Speaker: Matthew Forslund (Stony Brook University)

mforslund_Higgs_2021.pdf

mforslund.mp4

43 Sensitivity to invisible scalar decays at CLIC

An electron-positron Higgs factory is regarded as the highest-priority next large-scale collider facility. Among others, two linear collider projects are being considered: the Compact Linear Collider (CLIC) and the International Linear Collider (ILC). Reaching energies at the TeV scale, both machines would allow us not only to study Higgs boson and top quark properties with very high precision but could also result in the direct or indirect discovery of New Physics. SM-like Higgs boson or new heavy scalar decays with the emission of invisible dark matter particles could be the only way to observe Beyond the Standard Model effects at achievable energy scales and establish the connection between the Standard Model and New Physics sectors.

We studied the possibility of measuring the invisible Higgs boson and additional heavy scalar decays with CLIC running at 380 GeV and 1.5 TeV. The analysis is based on the WHIZARD event generation and fast simulation of CLIC detector response with DELPHES. We estimated the expected limits on the invisible decays of the 125 GeV Higgs boson, as well as the cross section limits for the production of an additional neutral scalar, assuming its invisible decays, as a function of its mass. The results obtained are one order of magnitude more stringent than the current limits coming from the LHC.

Speaker: Mr Krzysztof Mekala (University of Warsaw)

CLIC_sensitivity_to_invisible_scalar_decays_KMekala.pdf

Higgs21_KMekala.mp4

44 Testing anomalous H−W couplings and Higgs self-couplings via double and triple Higgs production at e+e− colliders

In the present work we study the implications at the future $e^+e^-$ colliders of the modified interaction vertices $WWH$, $WWHH$, $HHH$ and $HHHH$ within the context of the non-linear effective field theory given by the Electroweak Chiral Lagrangian. These vertices are given by four parameters, $a$, $b$, $\kappa_3$ and $\kappa_4$, respectively, that are independent and without any constraint from symmetry considerations in this non-linear effective Lagrangian context, given the fact the Higgs field is a singlet. This is in contrast to the Standard Model, where the vertices are related by $V_{WWH}^{\rm SM}=v V_{WWHH}^{\rm SM}$ and $V_{HHH}^{\rm SM}=v V_{HHHH}^{\rm SM}$, with $v=246$ GeV. We investigate the implications of the absence of these relations in the Electroweak Chiral Lagrangian case. We explore the sensitivity to these Higgs anomalous couplings in the two main channels at these colliders: double and triple Higgs production (plus neutrinos). Concretely, we study the access to $a$ and $b$ in $e^+e^- \to HH \nu \bar{\nu}$ and the access to $\kappa_3$ and $\kappa_4$ in $e^+e^- \to HHH \nu \bar{\nu}$. Our study of the beyond the Standard Model couplings via triple Higgs boson production at $e^+e^-$ colliders is novel and shows for the first time the possible accessibility to the quartic Higgs self-coupling.

Speaker: Manuel González-López (Universidad Autónoma de Madrid)

ManuelGonzalez_Higgs21.pdf

ManuelGonzalez_Higgs21_Video.mp4

16:00 Coffee Break

Time for watching pre-recorded videos of parallel sessions

Wednesday, 20 October

Time for watching pre-recorded videos of parallel sessions: (for people in Europe, Africa, Asia, Australia, etc)

Parallel: BSM: Live discussion session 1 [Room B]

Parallel B ZOOM Meeting: 637 8781 0364
Passcode: [please register to get this info]

Mattermost channel for discussions: https://mattermost.web.cern.ch/higgs2021/channels/bsm

Conveners: Luca Cadamuro (University of Florida (US)), Verena Ingrid Martinez Outschoorn (University of Massachusetts (US)), Zhen Liu (University of Minnesota)

Mattermost discussion

Zoom link B

45 Dark matter Phenomenology in two higgs doublet with complex scalar singlet model

Extensions of the two higgs doublet models with a singlet scalar can easily accommodate all current experimental constraints and are highly motivated candidates for Beyond Standard Model Physics. It can successfully provide a dark matter candidate, explain baryogenesis and provide gravitational wave signals. In this work, we focus on the dark matter phenomenology of the two higgs doublet model extended with a complex scalar singlet which serves as the dark matter candidate. We study the variations of the dark matter observables, i.e relic density and direct detection cross-section, with respect to the model parameters. We obtain a few representative benchmark points in the light and heavy dark matter mass region. We are also studying possible collider signatures of this model and the possibility of distinguishing this model from other new physics extensions.

Speaker: Juhi Dutta (University of Hamburg)

JuhiDutta_higgs2021.pdf

JuhiDutta_withSummary.pdf

zoom_0_JuhiDutta.mp4

46 Exotic Higgs decays at CMS

he latest results are presented in the search for exotic Higgs boson decays (lepton flavor-violating, h->aa), using the Run-2 data set collected by the CMS experiment.

Speaker: Tanvi Wamorkar (Northeastern University (US))

Higgs2021_Summary_Wamorkar.pdf

Higgs2021_Wamorkar.pdf

Higgs2021_Wamorkar_Recording.mp4

47 Searches for exotic and rare decays of the Higgs boson with the ATLAS detector

Exotic and rare decays of the Higgs boson provide a unique window for the discovery of new physics, as the Higgs boson may couple to hidden-sector states that do not interact under the Standard Model gauge transformations. Models predicting exotic Higgs boson decays to pseudoscalars can explain the galactic centre gamma-ray excess, if the additional pseudoscalar acts as the dark matter mediator. This talk presents recent ATLAS searches for decays of the 125 GeV Higgs boson to new particles, and searches for rare decays of the Higgs boson where enhanced rates would be a sign of new physics. These searches use LHC collision data at sqrt(s) = 13 TeV collected by the ATLAS experiment in Run 2.

Speaker: Kenji Hamano (University of Victoria (CA))

Higgs2021_KH.mp4

Higgs2021.pdf

48 Searches for low- and high-mass resonances with the ATLAS detector

Several theories beyond the Standard Model predict the existence of new particles decaying into pairs of gauge bosons. These states generally have masses larger than that of the Higgs boson, while some theories predict resonances with masses smaller than it. The latest ATLAS results on searches for such resonances in final states with leptons and photons based on pp collision data collected at 13 TeV will be presented.

Speaker: Liron Barak (Tel Aviv University)

ATLASSearchesLBsummary.pdf

LB_ATLAS.mp4

49 Measurement of Higgs production and search for an additional SM-like Higgs boson in the diphoton decay channel with the CMS detector

We present a recent analysis from the CMS Collaboration of the full run 2 dataset in which production properties of the Higgs boson are measured using the diphoton decay channel. All major Higgs boson production mechanisms are considered, enabling a wide range of cross section and coupling measurements to be performed. Highlights include the first CMS measurement of Higgs boson production in association with a single top quark in this decay channel and a simultaneous measurement of 27 independent Higgs boson production parameters. In addition, we present a search for an additional SM-like Higgs bosons in the diphoton final state.

Speaker: Muhammad Aamir Shahzad (Chinese Academy of Sciences (CN))

Higgs2021 Aamir.mp4

Higgs2021 Aamir.pdf

Higgs2021 Aamir_ Summary.pdf

50 Higgs searches at LHCb

LHCb is a spectrometer that covers the forward region of proton-proton collisions, in the pseudo rapidity range from 2 to 5. Thanks to the relatively background-free events in the high mass region, the precise reconstruction, and the trigger system with low energy thresholds, LHCb is the ideal place to search for (exotic) Higgs decays in a complementary space with respect to ATLAS and CMS. In this talk, the latest searches on BSM Higgs decays performed at LHCb will be presented, and the prospects for future LHC data-taking periods will be given. Moreover the possibility of observing the Standard Model H->bb and H->cc decays at LHCb in the future LHCb upgrades will be discussed.

Speaker: Davide Zuliani (Universita e INFN, Padova (IT))

presentation_zuliani_higgs.pdf

shortsummary_zuliani_higgs.pdf

video_zuliani_higgs.mp4

51 Multi-charged TeV scale Higgs bosons in the framework of a radiative seesaw model

Explaining the tiny neutrino masses and non-zero mixings have been one of the key motivations for going beyond the framework of the Standard Model (SM). We discuss a collider testable model for generating neutrino masses and mixings via radiative seesaw mechanism. That the model does not require any additional symmetry to forbid tree-level seesaws makes its collider phenomenology interesting. The model includes multi-charged fermions and Higgs bosons at the TeV scale to realize the Weinberg operator at 1-loop level. After deriving the constraints on the model parameters resulting from the neutrino oscillation data as well as from the upper bound on the absolute neutrino mass scale, we discuss the production, decay and resulting collider signatures of these TeV scale Higgs bosons at the Large Hadron Collider (LHC). We consider both Drell-Yan and photo-production. The bounds from the neutrino data indicate the possible presence of a long-lived multi-charged particle (MCP) in this model. We obtain bounds on these long-lived MCP masses from the ATLAS search for abnormally large ionization signature. When the TeV scale Higgs bosons undergo prompt decay, we focus on the 4-lepton final states and obtain bounds from different ATLAS 4-lepton searches.

Speaker: Mr Avnish . (Institute of Physics)

Avnish_higgs2021.mp4

Higgs2021.pdf

52 Higgs sector in Left-Right Mirror Model with Dark Matter

After observing a Higgs boson, the experiments with higher precision still agree with the Standard Model (SM). However, there are interesting topics related to the Higgs boson that may open the possibility of accepting a theory beyond the SM. For instance, the mechanism by which neutrinos obtain mass is still hidden, processes that involve neutral currents with flavor-changing and CP violation sources, and a candidate for dark matter (DM). These topics can be considered in the model presented in this work. The considered model is based on local gauge symmetry $SU(3)_C\times SU(2)_R\times SU(2)_L\times U(1)_{Y^\prime}$, named in the literature as LR. The LR model can also have a content of particles similar to the left sector but endowed with a right charge, known as mirror particles. From these additional particles one of the mirror neutrinos is proposed as candidate of DM. On the part of the scalar sector, the mirror doublet not only helps to break $SU(2)_R$ symmetry but also provides neutral and heavier Higgs-type scalar that gives an additional channel for the study of DM annihilation. Considering the last data reported by PLANCK Collaboration for non-baryonic content of the matter density, it has been found that heavy Higgs can have masses of the order of $ \sim 1$ TeV.

Speaker: Dr Jose Halim Montes de Oca Yemha (Universidad Nacional Autónoma de México)

Higgs2021_Halim.pdf

zoom_Higgs2021_halim.mp4

Parallel: Precision and Properties: Live discussion session 1 [Room A]

Parallel A ZOOM Meeting: 683 5990 0577
Passcode: [please register to get this info]

Mattermost channel for discussions: https://mattermost.web.cern.ch/higgs2021/channels/precisions-and-properties

Conveners: Alexander Yohei Huss (CERN), David Sperka (Boston University (US)), Hongtao Yang (Lawrence Berkeley National Lab. (US))

Mattermost discussion

Zoom link A

53 Studies of the CP properties of the Higgs boson at the ATLAS experiment

Studies of the CP properties of the Higgs boson in various production modes and decay channels are presented. Limits on the mixing of CP-even and CP-odd Higgs states are set by exploiting the properties of diverse final states.

Speaker: Chiara Arcangeletti (INFN e Laboratori Nazionali di Frascati (IT))

Arcangeletti_Higgs2021.mp4

Arcangeletti_Higgs2021.pdf

54 The CP character of the Higgs-fermion-fermion interactions: Interplay of collider physics, EDMs and baryogensis

An important goal in the investigation of the Higgs boson is the determination of its CP structure. In this talk, we investigate in detail constraints on the CP nature of the Higgs-fermion-fermion couplings. We take into account all relevant collider constraints in a global fit. Starting with simple effective models featuring CP violation in only one Higgs-fermion-fermion coupling, we successively allow for CP violation in more couplings. Moreover, we study the complementarity with electric dipole measurements and assess to which extent CP violation in the Higgs-fermion-fermion coupling can account for the baryon-antibaryon asymmetry of the Universe.

Speaker: Henning Bahl (Deutsches Elektronen-Synchrotron DESY)

Higgs2021_Henning_Bahl.mp4

Higgs2021_Henning_Bahl.pdf

55 Constraints on invisible Higgs decays from CMS

The latest results are presented in the search for Higgs boson decay to invisible signatures, using the Run-2 data set collected by the CMS experiment.

Speaker: Alp Akpinar (Boston University (US))

2021-10-20_higgs_cms.mp4

2021-10-20_higgs_cms_talk.pdf

56 Higgs boson properties from offshell production in ZZ to 2l2nu final state at CMS

Offshell production provides a unique way to measure the Higgs boson width and test unitarity in diboson production amplitudes. This process also adds sensitivity when constraining the Higgs boson anomalous couplings. In this talk, studies of offshell Higgs boson production in the ZZ to 2l2nu final state are presented, using Run 2 data from the CMS experiment. Results from the ZZ to 2l2nu final state are combined with published ZZ to 4l results to derive strong constraints.

Speaker: Mostafa Mahdavikhorrami (Universite Libre de Bruxelles (BE))

Higgs2021_hzz2l2nu_discussion.pdf

Higgs2021_hzz2l2nu.pdf

hzz2l2nu_Higgs2021.mp4

57 Off-shell Higgs Couplings in $H^*\to ZZ\to \ell\ell\nu\nu$

We explore the new physics reach for the off-shell Higgs boson measurement in the $pp \to H^* \rightarrow Z(\ell^{+}\ell^{-})Z(\nu\bar{\nu})$ 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 combination of a large signal rate and a precise phenomenological probe for the process energy scale, due to the transverse $ZZ$ mass, leads to significant sensitivities beyond the existing results in the literature for the new physics scenarios considered.

Speaker: Han Qin (University of Pittsburgh)

OffShell_Higgs2021.mp4

OffShell_Higgs2021.pdf

58 Directly Probing the Higgs-top Coupling at High Scales

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  $t\bar{t}h$. We study new physics effects for the Higgs-top coupling at high scales, using jet substructure techniques. We present the high-luminosity LHC sensitivity to new physics parametrized in the EFT framework and through a general Higgs-top form factor.

Speaker: Roshan Mammen Abraham (Oklahoma State University)

roshan_tth_high_scales_HIGSS2021.mp4

roshan_tth_high_scales_HIGSS2021.pdf

59 Development of novel experimental techniques to improve our understanding of the Higgs boson at the ATLAS experiment

With the full Run 2 pp collision dataset collected at 13 TeV by the ATLAS experiment, it is now possible to perform detailed measurements of Higgs boson properties in many production and decay modes. In many cases, novel experimental techniques were developed to allow for these measurements. This talk presents various such techniques, including embedding of simulated objects in data; special object weighting techniques to maximize statistical precision; developing special trigger, reconstruction, and identification algorithms for non-standard objects; special treatments of sources of two-point theory systematic uncertainties; and special developments in likelihood-based fitting techniques.

Speaker: Matthew Henry Klein (University of Michigan (US))

mk_higgs20211006 (3).pdf

mk_higgs20211006_recording.mp4

mk_summary_higgs20211006.pdf

60 Electroweak Restoration at the LHC and Beyond: The Vh Channel

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 boson equivalence theorem. This convergence is most easily measured in the vector boson plus Higgs production, Vh, which is dominated by the longitudinal polarizations. We define EW restoration by carefully taking the limit of zero Higgs vacuum expectation value (vev). We demonstrate that the 14 TeV HL-LHC can confirm that this ratio converges to one to 40% precision while at the 27 TeV HE-LHC the precision will be 6%. We also investigate statistical tests to quantify the convergence at high energies. Our analysis provides a roadmap for how to stress test the Goldstone boson equivalence theorem and our understanding of spontaneously broken symmetries, in addition to confirming the restoration of EW symmetry.

Speaker: Ian Lewis (The University of Kansas)

GMT20211018-183007_Recording_as_1600x900.mp4

IL_Higgs_2021.pdf

61 Optimising the performance of the CMS Electromagnetic Calorimeter in LHC Run 2 for the measurement of Higgs boson properties

The CMS Electromagnetic Calorimeter (ECAL), is a high granularity lead tungstate crystal calorimeter operating at the CERN LHC. The original design placed a premium on excellent energy resolution for the discovery and subsequent characterisation of the Higgs boson. Excellent energy resolution and efficient identification for photons are essential to reconstruct the Higgs boson in the H->gg decay channel, for measurements of the mass, signal strength and other related properties of the Higgs boson.

A full recalibration of the CMS ECAL has recently been performed using the full LHC Run 2 (2015-2018) dataset. The stability of the energy response versus time is ensured by a dedicated laser-based monitoring system, together with additional time-dependent corrections derived from physics events. A dedicated calibration of each detector channel has also been performed, exploiting electrons from W and Z boson decays, photons from pi0/eta decays, and the azimuthally symmetric energy distribution of minimum bias events. These refined calibrations have resulted in significant improvements in ECAL energy resolution and energy scale stability, compared to the preliminary calibrations that have previously been used in the analysis of Run 2 data.

This talk will present the ECAL calibration strategies that have been implemented and the resulting performance achieved by the ECAL for LHC Run 2. The potential impact of these improvements on measurements of Higgs boson properties will also be described.

Speaker: Chiara Amendola (CEA Paris-Saclay (FR))

amendola_ecal.mp4

amendola_ecal.pdf

Parallel: Snowmass/Future colliders: [Room C]

Parallel C ZOOM Meeting: 617 4486 8526
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Conveners: Caterina Vernieri (SLAC National Accelerator Laboratory (US)), Isobel Ojalvo (Princeton University (US)), Sally Dawson (BNL)

Mattermost discussion

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62 Study of b- and c-jets identification for Higgs coupling measurements at Muon Collider

The Muon Collider is a possible option for the next generation of high energy collider machines. It would permit to achieve very high energy in the center of mass using leptons without occurring in a significative synchrotron radiation losses as in the electrons rings. Due to the muon decay, the detector has to sustain a high level of background: beam decay products and subsequent particles from secondary interactions with the machine elements can reach the interaction point, limiting the physical performances of the detector. Nevertheless, this machine offers the possibility to produce a lot Higgs bosons events to allow the precise determination of the b- and c-quark couplings. In this talk studies on the identification of b- and c-jets in the Muon Collider environment will be presented. Prospects on the measurement of the Higgs couplings to the b- and c-quark will be discussed.

Speakers: Giacomo Da Molin, Giacomo Da Molin

GDM_bcjetsatMuonCollider.mp4

Study of b- and c-jets identification for Higgs coupling measurements at Muon Collider.pdf

63 Prospects for the measurement of σH x BR(H → μμ) at a 3-TeV muon collider

Among the projects currently under study for the next generation of particle accelerators, the muon collider represents a unique machine, which has the capability to provide leptonic collisions at energies of several TeV. The multi-TeV energy regime is as yet unexplored and holds a huge physical potential that will enable a novel research programme ranging from high precision measurements of known standard model processes to high-sensitivity searches for phenomena beyond the standard model.
A multi-TeV muon collider will produce huge samples of Higgs bosons that will allow a precise determination of the Higgs boson properties, like its couplings to fermions and bosons and its trilinear and quartic self-couplings with unprecedented precision.
This contribution will present an estimate of the muon collider reach on the production of the process H → μμ, one of the rarest Higgs boson decays that represents a gateway to the determination of the Higgs boson coupling to the second generation leptons.

Speaker: Alessandro Montella (University of Trieste and INFN-Trieste)

Higgs2021_montella.mp4

montella_Higgs_2021.pdf

64 Flavor-Tagging of Quark Pairs at e+e- Higgs/Top Factories

At e+e- colliders, it is possible to separately measure the branching ratios for Higgs decays to bb, cc, and light quark and gluon jets. However, this imposes extraordinary requirements on heavy quark tagging. We have been studying the capabilities of e+e- detectors for heavy quark tagging using the reactions e+e- -> qq, with qq = cc, bb, tt at 250 and 500 GeV. We will show with detailed simulations using the ILD detector concept that the production rates and the forward-backward asymmetries of all three processes can be measured at the 0.1% - 0.5% level, and we will explain how systematic errors can be controlled to reach this level of accuracy. It is possible to achieve superb measurements of secondary and tertiary vertices and measurement of the vertex charges to distinguish quarks from antiquarks. We will also comment on the direct relevance of these 4-fermion reactions to electroweak symmetry breaking by showing their discovery potential for Randall-Sundrum models with warped extra dimensions.

Speaker: Adrian Irles (IFIC CSIC/UV)

Higgs2021_Irles_v3.pdf

zoom_2.mp4

65 A combined fit to the Higgs Branching Ratios at ILD

We introduce here a new method to measure the Higgs decay branching ratios at future e⁺e⁻ Higgs factories, by directly exploiting class numeration.
Given the clean environment at a lepton collider, we build an event sample highly enriched in Higgs bosons and essentially unbiased for any decay mode.
The sample can be partitioned into categories using event properties linked to the expected Higgs decay modes.
The counts per category are used to fit the Higgs branching ratios in a model independent way.
The result of the fit is directly the set of branching ratios, independent from any measurement of a Higgs production mode.
Special care is given to an appropriate treatment of the statistical uncertainties.
In this contribution, the current status of our implementation of this analysis within the ILD concept detector is presented.

Speaker: Jonas Kunath (LLR IPP/CNRS)

Higgs2021_JonasKunath.mp4

Higgs2021_JonasKunath_v2.pdf

66 Prospects of Higgs self-coupling measurements at the ILC using ILD detector

Higgs self-coupling measurement provides a direct probe of the Higgs potential, which is important both for understanding of electroweak symmetry breaking and for testing of electroweak baryogenesis models. In this talk we will present studies addressing two aspects about the Higgs self-coupling measurement at the ILC at the center-of-mass energies of 500 GeV and 1 TeV. The first one is for the measurements of double Higgs production cross sections, based on the full detector simulation using the ILD and by including all SM background processes. The second one is how the prospect of Higgs self-coupling measurement would drastically change if its value is largely deviated with its SM expected as suggested by EW baryogengesis models. The talk will also point out some experimental opportunities such as how better flavor-tagging and jet-clustering algorithms would help improve Higgs self-coupling measurements.

Speaker: Taikan Suehara (Kyushu University (JP))

211020-higgs2021-suehara-higgssc.pdf

211020-higgs2021-suehara-higgssc-sound.mp4

67 Electron Yukawa determination

Measuring the electron Yukawa is impossible in Higgs boson decays, H -> e+e- , given the smallness of the electron mass that leads to a vanishingly small decay branching fraction. The only direct method to extract the Higgs-electron coupling is through resonant s-channel production in e+e- collisions running at the Higgs pole mass. Such a measurement is possible at the FCC-ee provided one can monochromatize the beams, leading to a center-of-mass energy spread not much larger than the Higgs boson width of ~4 MeV, as well as having a prior accurate and precise knowledge of the Higgs boson mass, within MeV uncertainties. Under such conditions, a study combining 10 different Higgs decay modes indicates that a ~1.3sigma significance for the e+e- -> H process can be reached, above the (much larger) backgrounds, for every 10 ab-1 of integrated luminosity per FCC-ee interaction point (IP). Depending on the number of IPs and years running at the Higgs pole, such a measurement will provide the only means known to access the electron Yukawa.

Speaker: David d'Enterria (CERN)

ee_Higgs_schannel_FCCee_Higgs21 (slides for online discussion).pdf

electron Yukawa from Higgs s-channel at FCC-ee (15' PDF presentation instead of VIDEO)

68 FCC synergies for Higgs physics

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 well as searches for exotic and invisible decays. Very high energy proton-proton collision (up to 100 TeV) provided by the FCC-hh will allow studying the Higgs self-coupling. There is a remarkable complementarity of the FCC-ee and FCC-hh colliders, which in combination offer the best possible overall study of the Higgs boson properties.

Speaker: Matthew Philip Mccullough (CERN)

Higgs2021.pdf

synergies.mp4

69 ZH and mH studies at FCC-ee

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 well as searches for exotic and invisible decays. This talk discusses the model-independent measurement of the Higgs boson coupling to Z bosons and the Higgs boson mass.

Speaker: Ang Li (APC, CNRS/IN2P3 and Université de Paris)

2021_10_20_FCC_HIGGS2021_Ang_LI.mp4

2021_10_20_FCC_HIGGS2021_Ang_LI.pdf

2021_10_20_FCC_HIGGS2021_Ang_LI_short.pdf

70 C3: An Advanced Concept for a e+e- Linear Collider

The goal of a next-generation e+e- collider is to carry out precision measurements to per-cent level of the Higgs boson properties that are not accessible at the LHC and HL-LHC. In this talk will we present the study of a new concept for a high gradient, high power accelerator with beam characteristics suitable to study the Higgs boson, the Cool Copper Collider (C3), with the goal of significantly reducing capital and operating costs. We will present a timeline for such a collider to enable Higgs boson precision measurements exploring increasing energies for the center-of-mass collisions. The exploitation of the complementarity between HL-LHC and future e+e- colliders will be the key to exploring the Higgs sector.

Speakers: Emilio Nanni (SLAC National Accelerator Laboratory), Emilio Nanni

higgs-c3-Higgs2021v4_post.pdf

recording_higgs-c3-Higgs2021v4_post.mp4

10:00 Coffee Break

Plenary: DiHiggs

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Convener: Elizabeth Brost (Brookhaven National Laboratory (US))

Zoom

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71 ATLAS: “Di-Higgs results - twice the Higgs, twice the fun" (20+10)

Speaker: Marco Valente (TRIUMF (CA))

DiHiggs_plenary_MarcoValente_Higgs2021.pdf

Video recording

72 CMS: “Di-Higgs results - twice the Higgs, twice the fun" (20+10)

Speaker: Petar Maksimovic (Johns Hopkins University (US))

Maksimovic_higgs21.pdf

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73 “BSM targets for Di-Higgs searches” (20+10)

Speaker: Daniel Egana-Ugrinovic (Perimeter Institute)

di-Higgs.pdf

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74 “SM theory for HH: signal and background” (20+10)

Speaker: Javier Mazzitelli (Max-Planck-Institut fur Physik (DE))

HH_mazzitelli.pdf

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Plenary: Young Scientist talks

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Convener: Paul Grannis (Stony Brook University (US))

Zoom

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75 Search for non-resonant di-Higgs production in the bbyy final state at 13 TeV with the ATLAS experiment

The bbγγ channel is one of the most sensitive HH final states for measuring the Higgs self-coupling and di-Higgs production cross-section. This analysis capitalizes on the clean signature of the two photons in the final state combined with the high branching ratio of H→bb. This talk will present the latest non-resonant ATLAS HH→ bbγγ results with the full Run 2 dataset of 139/fb at 13 TeV. The analysis uses a multivariate approach to target high and low HH mass regions to maximize the sensitivity to modifications of the Higgs self-coupling. This result sets the observed (expected) upper limits on the non-resonant HH production cross-section at a 95% confidence level at 130 fb (180 fb), which corresponds to 4.1x (5.5x) the Standard Model value. The analysis provides the strongest observed (expected) limits on the self-coupling of -1.5 to 6.7 (-2.4 to 7.7) to date.

Speaker: Jannicke Pearkes (SLAC National Accelerator Laboratory (US))

Higgs_2021_JP.pdf

Video recording

76 Higgs Physics at a Muon Collider

Muon collisions at multi-TeV center of mass energies are ideal for studying Higgs boson properties. At these energies the production rates will allow precise measurements of its couplings to fermions and bosons. In addition the double Higgs boson production rate could be sufficiently high to directly measure the parameters of trilinear self-couplings, giving access to the determination of the Higgs potential.
This contribution aims to give an overview of the results that have been obtained so far on Higgs couplings by studying the 𝜇+𝜇−→𝐻𝜈𝜈¯ and 𝜇+𝜇−→𝐻𝐻𝜈𝜈¯ processes. All the studies have been performed by fully simulating the signal and physics background samples and by evaluating the effects of the beam-induced background on the detector performances.
Evaluations on Higgs boson couplings sensitivities and most recent results on the uncertainty on double Higgs production cross section, together with the trilinear self-coupling, will be discussed at 𝑠√ of 3 TeV and extrapolated to 10 TeV.

Speaker: Luca Giambastiani (Universita e INFN, Padova (IT))

H21.pdf

HiggsPhysicsMuonCollider.mp4

77 Charm-jet tagging at the LHCb experiment

LHCb is a spectrometer that covers the forward region of proton-proton collisions.
Thanks to its excellent vertex reconstruction system, it has already demonstrated its capability to identify heavy flavour jets. Moreover, the c-jet identification (c-tagging) is a crucial ingredient for the search of H->cc at LHCb. In this talk, the c-tagging algorithm used at LHCb will be illustrated, as well as recent applications and measurements that employ it. The methods used to calibrate the c-tagging algorithm and the determination of its performance will be discussed. Finally, prospects on the search for H->cc in future upgrades will be given.

Speaker: Thomas Boettcher (University of Cincinnati (US))

Boettcher_Higgs_20Oct2021_v2.pdf

CharmjetTaggingLHCb.mp4

13:00 Lunch Break

Pub Quiz

Intro slides for Virtual Pub quiz.pdf

Zoom (use same passcode as for plenaries)

Plenary: BSM

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Convener: Luca Cadamuro (University of Florida (US))

Zoom

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78 ATLAS+CMS: “Exotic and invisible decays of the observed Higgs boson” (20+10)

Speaker: Scott Snyder (Brookhaven National Laboratory (US))

2021-10-higgs.pdf

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79 ATLAS+CMS: “Searches for additional scalar or Higgs-like particles” (20+10)

Speaker: Fabio Ravera (Fermi National Accelerator Lab. (US))

FRavera_Higgs2021.pdf

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80 “BSM Higgs: new states, exotic and invisible decays” (20+10)

Speaker: Zhen Liu (University of Minnesota)

Higgs2021_HiggsExoticDecays_ZhenLiu_Oct2021.pdf

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16:00 Coffee Break

Time for watching pre-recorded videos of parallel sessions

Thursday, 21 October

Time for watching pre-recorded videos of parallel sessions: (for people in Europe, Africa, Asia, Australia, etc)

Plenary: EFT

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Convener: Andrei Gritsan (Johns Hopkins University (US))

Zoom

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81 Is SMEFT enough?

Speaker: Tim Cohen (University of Oregon)

Is SMEFT Enough?_Higgs2021.pdf

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82 “EFT tools and global fits” (20+10)

Speaker: Ilaria Brivio (University of Heidelberg)

Higgs2021_Brivio.pdf

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83 ATLAS+CMS: “EFT results from Higgs and beyond” (20+10)

Speaker: Marco Battaglia (University of California,Santa Cruz (US))

Higgs2021-MB.pdf

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10:30 Coffee Break

Plenary: Theory input & experimental tools

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Convener: Michelangelo Mangano (CERN)

Zoom

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84 ATLAS+CMS: “Modelling of signal and background processes: where is a better understanding needed to make progress” (15+15+10)

Speakers: Adinda De Wit (Universitaet Zuerich (CH)), Nicolas Morange (Université Paris-Saclay (FR))

Modelling_Higgs21.pdf

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85 “MC modelling of Higgs signals and backgrounds” (20+10)

Speaker: Frank Siegert (Technische Universitaet Dresden (DE))

2021-10-21-Higgs-2021.pdf

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86 “Parton Showers” (20+10)

Speaker: Simon Platzer (University of Vienna (AT))

slides-reduced.pdf

VideoSimonMC.mp4

Plenary: Young Scientist talks

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Mattermost channel for discussions for Thursday plenary EFT session: https://mattermost.web.cern.ch/higgs2021/channels/plenary-thu-eft

Mattermost channel for discussions for Thursday plenary Theory input and experimental tools session: https://mattermost.web.cern.ch/higgs2021/channels/plenary-thu-theoryexp-tools

Mattermost channel for discussions for Friday plenary Future and Closing session: https://mattermost.web.cern.ch/higgs2021/channels/plenary-fri

Convener: John David Hobbs (Stony Brook University (US))

Zoom

Mattermost discussion channels

• Friday Future and Closing (plenary)
• Monday Opening 1&2 (plenary)
• Thursday EFT (plenary)
• Thursday Theory input and experimental tools (plenary)
• Tuesday Flavor (plenary)
• Tuesday Properties and Precision (plenary)
• Wednesday BSM (plenary)
• Wednesday DiHiggs (plenary)
• Young Scientist Fora (all days, plenary)

87 Strange Quark as a Probe for New Physics in the Higgs Sector

A crucial element of the study of the Higgs boson is the measurement of its couplings to the fermions of the second generation. Experiments at the Large Hadron Collider (LHC) have recently reported the first evidence for the Higgs boson coupling to the muon. It is equally important to measure the Higgs boson coupling to the charm and strange quarks. These decay modes are nearly impossible to measure with precision at the LHC due to the limited detector capabilities and large irreducible backgrounds. The situation is better at e+e- colliders, but the identification of strange quark decays of the Higgs boson remains a challenge. One needs an efficient algorithm to distinguish jets originating from strange quarks from those initiated by lighter quarks. Also, one must deal with backgrounds due to strange production in heavy-quark jets. In this talk we will present a first version of a strange quark tagger and the first projected sensitivity estimates for the coupling of the Higgs boson to strange quarks at future e+e- colliders . The studies make use of the International Large Detector (ILD) simulations for the International Linear Collider, but the methodology and the results are expected to be similar for other proposed e+e- Higgs factories.

Speaker: Matthew Basso (University of Toronto (CA))

211021_Basso_Higgs2021_Hss-with-ILD_v3.pdf

Video recording

88 Measurements of Higgs boson production cross sections in the H -> ττ decay channel in pp collisions at √s = 13 TeV with the ATLAS detector

The coupling of the Higgs boson to tau leptons is one of the most precise measured couplings of the Higgs boson to fermions. A measurement of the production cross sections of the Higgs boson into two tau leptons is presented. The cross section is measured in the gluon-fusion, vector-boson-fusion, boson associated, and top-quark pair associated production channels. The result is shown in the context of Simplified Template Cross Sections. The study illustrates the technique for the Higgs boson mass reconstruction (Missing Mass Calculator, MMC). The analysis uses proton-proton collision data recorded during Run 2 at a center-of-mass energy sqrt(s) = 13 TeV with the ATLAS detector at the LHC.

Speaker: Kristina Mihule (Charles University (CZ))

Mihule_Htautau_ATLAS.pdf

Video recording

13:00 Lunch Break

Parallel: BSM: Live discussion session 2 [Room B]

Parallel B ZOOM Meeting: 637 8781 0364
Passcode: [please register to get this info]

Mattermost channel for discussions: https://mattermost.web.cern.ch/higgs2021/channels/bsm

Conveners: Luca Cadamuro (University of Florida (US)), Verena Ingrid Martinez Outschoorn (University of Massachusetts (US)), Zhen Liu (University of Minnesota (US))

Mattermost discussion

Zoom link B

89 First Order Electroweak Phase Transition from Weakly Coupled sub-GeV Physics

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 transition, through dimension-5 interactions of $\phi$ suppressed by scales from $O(10^3)$ TeV to near Planck mass. The scalar $\phi$ is long-lived and can yield missing energy signals in rare kaon decays.

Speaker: Hooman Davoudiasl (BNL)

HDavoudiasl-Higgs2021.mp4

HDavoudiasl-Higgs2021-Summary.pdf

90 Collider and Gravitational Wave Complementarity in the 2HDM

The Higgs potential is crucial for us to understand the mechanism of EWSB. We show how collider measurements and observations of stochastic gravitation wave can complement each other to explore the scalar potential in the 2HDM scenario. Through a comprehensive study, accouting for theoretical and current experimental constraints, we study the key ingredients in the shape of the Higgs potential triggering the strong first order phase transition and compare the dominant collider signals at the HL-LHC. We obtain that the heavy Higgs searches with fermionic decay, $H/A/H^\pm\to ff$, are the leading smoking gun signatures of strong first order EWPT in the 2HDM.

Speaker: Dr Yongcheng Wu (Oklahoma State University)

ycwu_Higgs2021.mp4

ycwu_Higgs2021.pdf

91 Searches for additional Higgs bosons in ATLAS

The discovery of the Higgs boson with the mass of about 125 GeV completed the particle content predicted by the Standard Model. Even though this model is well established and consistent with many measurements, it is not capable to solely explain some observations. Many extensions of the Standard Model addressing such shortcomings introduce additional Higgs-like bosons which can be either neutral, singly-charged or even doubly-charged. The current status of searches based on the full LHC Run 2 dataset of the ATLAS experiment at 13 TeV are presented.

Speaker: Yanjun Tu (University of Hong Kong (HK))

ATL-COM-PHYS-2021-890_v3_.pdf

GMT20211019-143541_Recording_1600x800.mp4

92 Searches for additional heavy neutral and charged Higgs bosons in final states with fermions at CMS

The latest results on searches for additional neutral and charged Higgs bosons at CMS are presented. The results include searches for additional Higgs bosons decays into pairs of fermions and charged Higgs boson decays with fermionic final states.

Speaker: Aliaksei Raspiareza (Deutsches Elektronen-Synchrotron (DE))

AlexeiRaspereza-HiggsBSM.mp4

Higgs2021_ARaspereza.pdf

Higgs2021_Summary.pdf

93 Searches for resonances decaying to boson pairs in ATLAS

Many new physics models predict the existence of Higgs-like particles decaying into two bosons (W, Z, photon, or Higgs bosons) making these important signatures in the search for new physics. Searches for spin-0 diboson resonances have been performed in final states with different numbers of leptons, photons, as well as jets and b-jets where new jet substructure techniques are used to disentangle the hadronic decay products in highly boosted configuration. This talk summarises recent ATLAS searches with Run 2 data collected at the LHC and explains the experimental methods used, including vector- and Higgs-boson-tagging techniques.

Speaker: Allison Mccarn Deiana (Southern Methodist University (US))

Higgs2021_Deiana_SummarySlides.pdf

Higgs2021_Deiana_Talk.mov

Higgs2021_HtoBosons_final.pdf

Parallel: Precision and Properties: Live discussion session 2 [Room A]

Parallel A ZOOM Meeting: 683 5990 0577
Passcode: [please register to get this info]

Mattermost channel for discussions: https://mattermost.web.cern.ch/higgs2021/channels/precisions-and-properties

Conveners: Alexander Yohei Huss (CERN), David Sperka (Boston University (US)), Hongtao Yang (Lawrence Berkeley National Lab. (US))

Mattermost discussion

Zoom link A

94 Exact top-quark mass dependence in hadronic Higgs production

The impact of the finite top-quark mass on the inclusive Higgs
production cross section at higher perturbative orders has been an open
question for almost three decades. In this talk, I report on the
computation of this effect at NNLO QCD. For the
purely gluonic channel, it amounts to $+0.62\%$ relative to the result
obtained in the HEFT approximation. The formally sub-leading
partonic channels over-compensate this shift, leading to an overall
effect of $-0.26\%$ at a $pp$ collider energy of $13\,\mathrm{TeV}$, and $-0.1\%$
at $8\,\mathrm{TeV}$. This result eliminates one of the main theoretical
uncertainties to inclusive Higgs production cross section at
the LHC.

Speaker: Mr Marco Niggetiedt (RWTH Aachen University)

Niggetiedt_Higgs_2021.mp4

Niggetiedt_Higgs_2021.pdf

95 Fiducial predictions for the Higgs Transverse Momentum at N3LL'+NNLO

We present state-of-the-art predictions for the transverse momentum of
the colour singlet in gluon-fusion Higgs production. We resum this observable at N$^3$LL’ accuracy in momentum space with the RadISH formalism, thus consistently including in our prediction all constant terms of relative order $\alpha_s^3$ with respect to the Born. We supplement our results with a transverse-recoil prescription, accounting for dominant classes of subleading-power corrections in a fiducial setup. The resummed predictions are then matched with fixed-order differential spectra at NNLO accuracy and compared with 13 TeV LHC data relevant to the Higgs to di-photon channel.

Speakers: Emanuele Re (Unite Reseaux du CNRS (FR)), Dr Luca Rottoli (Universitaet Zuerich (CH)), Paolo Torrielli (Universita e INFN Torino (IT))

rottoli_talk_Higgs_2021.pdf

zoom_recording_rottoli.mp4

96 The Higgs pT Spectrum and Total Cross Section with Fiducial Cuts at N3LL'+N3LO

I present predictions for the gluon-fusion Higgs $p_T$ spectrum at N$^3$LL$'$+N$^3$LO including fiducial $H \to \gamma\gamma$ cuts as required by experimental measurements at the LHC. Integrating the spectrum allows us to predict for the first time the total fiducial cross section to third order (N$^3$LO) and improved by resummation. I discuss several aspects of the calculation, including

• the treatment of fiducial power corrections that make the total cross section sensitive to small-$p_T$ resummation effects, and in particular enhance the N$^3$LO correction,
• the numerical extraction of the remaining nonsingular corrections at $\mathcal{O}(\alpha_s^3)$, and
• extensions to other differential Higgs cross sections at three loops, including the Higgs rapidity spectrum and the diphoton rapidity separation, where a similar sensitivity to resummation effects arises.

Speaker: Johannes Michel (MIT CTP)

Johannes_Michel_Higgs_2021.mp4

Johannes_Michel_Higgs_2021.pdf

Johannes_Michel_Higgs_2021_summary_slides.pdf

97 Fully Differential Prediction for Higgs Boson Production at N3LO

I present state of the art predictions for differential distributions of the decay products of the Higgs boson.
In particular, I demonstrate the impact of next-to-next-to-next-to leading order (N3LO) QCD corrections to the gluon fusion production mechanism. The impact of this newly obtained corrections is required to fully exploit the physics potential of the LHC.

Speaker: Bernhard Mistlberger (SLAC National Accelerator Laboratory (US))

Higgs2021_Mistlberger.mp4

Higgs2021.pdf

98 Measurements and interpretations of Simplified Template Cross Sections, differential and fiducial cross sections in Higgs boson decays to four leptons with the ATLAS detector

Higgs boson decays to four leptons can be selected with a very high purity and are very well suited for measurements of Higgs boson properties, despite the small H -> ZZ* -> 4l branching ratio. This talk will present measurements of differential cross sections, as well as cross section measurements for the different Higgs boson production processes in the Simplified Template Cross Section framework using pp collision data collected at 13 TeV.

Speaker: Samyukta Krishnamurthy (University of Massachusetts (US))

Krishnamurthy_Higgs2021_FidDiffSTXS_4lep_ATLAS.pdf

Krishnamurthy_Higgs2021_Updated.mp4

99 Measurement of the Higgs cross sections in the H->ZZ->4l channel at CMS

The talk will present the Run2 legacy measurement on Higgs cross-sections (STXS, fiducial, and differential) in the H->ZZ->4l performed by the CMS collaboration.

Speaker: Walaa Elmetenawee (Universita e INFN, Bari (IT))

Higgs2021_HZZ4l.mp4

Higgs2021_HZZ4l.pdf

Parallel: Yukawa: Live discussion session 1 [Room C]

Parallel C ZOOM Meeting: 617 4486 8526
Passcode: [please register to get this info]

Mattermost channel for discussions: https://mattermost.web.cern.ch/higgs2021/channels/yukawa

Conveners: Clara Murgui, Nicolas Morange (Université Paris-Saclay (FR)), Patrick Meade, Stephane Brunet Cooperstein (Univ. of California San Diego (US))

Mattermost discussion

Zoom link C

100 Measurements and interpretations of Higgs boson production using decays to two b-quarks with the ATLAS detector

Testing the couplings of the Higgs boson to quarks is important to understand the origin of quark masses. The talk presents Simplified Template Cross Section measurements for Higgs boson production in association with a vector boson using decays to two b quarks using pp collision data collected at 13 TeV, along with an interpretation in an Effective Field Theory framework. A search for vector-boson fusion production in the same Higgs decay channel will also be presented.

Speaker: Maria Giovanna Foti (University of Oxford (GB))

Higgs2021_FotiMG_Hbb.mp4

Higgs2021_FotiMG_Hbb.pdf

101 Higgs boson decays into b and c quarks with the CMS experiment

We present the latest CMS results on the measurement of Higgs boson production with H->bb decays, considering production in association with a vector boson and via vector boson fusion or gluon fusion. In addition, we discuss the latest searches for H->cc decays.

Speaker: Sam Kaveh (Deutsches Elektronen-Synchrotron (DE))

higgs2021_kaveh.mp4

Higgs decays to fermions(4).pdf

102 Higgs boson coupling to second generation fermions with the ATLAS detector

Searches for Higgs boson decays to two second-generation quarks or leptons, based on 13 TeV pp collision data, are presented, as well as indirect constraint of the Yukawa coupling of the Higgs boson to the charm quark.

Speaker: Maria Mironova (University of Oxford (GB))

Higgs2021_Mironova.mp4

Higgs2021_Mironova.pdf

Mironova_Higgs2021_short.pdf

103 Rare Higgs decays at CMS

The latest results are presented for rare decays of the Higgs boson (H->ee, H->mumu, H->Zg, ...), using the Run-2 data set collected by the CMS experiment.

Speaker: James Dale Bueghly (Northwestern University (US))

cms_rare_decays_bueghly_higgs2021.mp4

cms_rare_decays_bueghly_higgs2021_vf.pdf

104 Search for rare and lepton flavor violating decays of the Higgs boson with the ATLAS detector

The Standard Model predicts several rare Higgs boson decay channels, among which are decays to a Z boson and a photon, H to Zgamma, and to a low-mass lepton pair and a photon H to llgamma. The observation of these decays could open the possibility of studying the CP and coupling properties of the Higgs boson in a complementary way to other analyses. In addition, lepton-flavor-violating decays of the observed Higgs boson are searched for, where on observation would be a clear sign of physics effects beyond the Standard Model. Several results for decays based on pp collision data collected at 13 TeV will be presented.

Speaker: Tom Neep (University of Birmingham (GB))

Neep-Higgs21.pdf

neep-summary.pdf

Searches for rare and LFV decays of the Higgs boson with ATLAS.mp4

105 Higgs to charm quarks in vector boson fusion plus a photon

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. We discuss the trigger implications of this final state that can be utilized in ATLAS and CMS. We propose a novel search strategy for $H\to c\bar c$ in association with VBF jets and a photon, where we find a projected sensitivity of about 5 times the SM charm-Yukawa coupling at 95$\%$ $\text{CL}_s$ at High Luminosity LHC (HL-LHC). Our result is comparable and complementary to existing projections at the HL-LHC. We also discuss the implications of increasing the center of mass collision energy to 30 TeV and 100 TeV.

Speaker: Sze Ching Iris Leung (University of Pittsburgh)

Higgs2021.pdf

video1272282562.mp4

15:30 Coffee Break

Parallel: Joint Future/BSM: Live discussion session 2 [Room B]

Parallel B ZOOM Meeting: 637 8781 0364
Passcode: [please register to get this info]

Mattermost channel for discussions: https://mattermost.web.cern.ch/higgs2021/channels/joint-futurebsm

Conveners: Caterina Vernieri (SLAC National Accelerator Laboratory (US)), Isobel Ojalvo (Princeton University (US)), Luca Cadamuro (University of Florida (US)), Sally Dawson (BNL), Verena Ingrid Martinez Outschoorn (University of Massachusetts (US)), Zhen Liu (University of Minnesota)

Mattermost discussion

Zoom link B

106 Higgs decays (partially) into the dark: towards the Higgs "neutrino floor"

We investigate semi-invisible Higgs decays $h \to Z X$ (with $X$ an invisible particle) as probes of the possible interactions of the Higgs boson with a dark sector. This possibility can occur in dark matter models with a low-mass pseudoscalar mediator to the dark sector, as well as in models of axion-like particles or dark photons interacting with the Higgs boson. The SM decay $h \to Z\nu\nu$ constitutes a "neutrino floor" for this type of search (and provides a sensitivity target for the search), and we study the window that is left for probing new physics via $h \to Z X$ at the LHC and future colliders.

Speaker: Jose Miguel No (IFT-UAM/CSIC)

Higgs_2021_JMNo_Final.pdf

JMNo_Higgs2021.mp4

107 Higgs boson CP properties at CEPC

The next generation collider, CEPC, will operate at sqrt(s)=240 GeV as the Higgs factory to provide a clean environment for precise measurement of Higgs properties. With the expected integrated luminosity of 5.6 /ab, the CEPC will be able to reach the accuracy for Higgs CP property much better than HL-LHC. Thus the anomalous coupling in the presence of BSM physics can be searched with unprecedented sensitivity. More importantly, the coupling can be studied in both ee->Z->ZH and H->ZZ processes to get a better knowledge of q^2-dependence. This talk will summarize the expected results of Higgs CP, and anomalous coupling, fa2 and fa3, with a BDT study of the angular distributions based on MC simulations in CEPC. The sensitivity is significantly improved compared to that from HL-LHC.

Speaker: Ke Li (University of Washington (US))

CEPC Higgs CP.pdf

zoom_3.mp4

108 Probing anomalous WWH/ZZH couplings at the ILC

This talk will introduce the full detector simulation analyses of anomalous WWH coupling measurements at the ILC. One method is as same as that at LHC, using differential distributions in H—>WW decay channel. At the ILC essentially all decay channels of WW including the fully hadronic channel can be utilized. Charm-tagging is very useful in order to get more complete differential distributions. Identifying the charge of charm-jets will also be helpful to determine the charge of Ws in fully hadronic decays. Another method to probe anomalous WWH at the ILC is to use the differential cross section for the production channel e+e- —> nu nubar H via WW-fusion, which becomes significant and very useful at a CM energy of 500 GeV.

Speaker: Tomohisa Ogawa (High Energy Accelerator Research Organization)

Higgs2021_211021_long.pdf

Higgs2021_211021_v00.mp4

109 Higgs as a probe of beyond the Standard Model physics

The minimal U$(1)_X$ extension of the Standard Model (SM) is a simple and well-motivated extension of the SM, which supplements the SM with the seesaw mechanism for naturally generating the light neutrino masses and offers various interesting phenomenologies.In the model, the U$(1)_X$ charge of each SM field is characterized by the U$(1)_X$ charge of the SM Higgs doublet with a free parameter $x_H$ and $x_\Phi$. Due to the U$(1)_X$ charge of the Higgs doublet, the Higgs boson has a trilinear coupling with the $Z$ and the U$(1)_X$ gauge boson $(Z^\prime)$ due to $x_H\neq 0$. With this coupling, a new process for the associated Higgs boson production with $Z$ boson arises through a $Z^\prime$ boson in the $s$-channel at high energy colliders. In this paper, we calculate the associated Higgs boson production at high energy colliders and show the interesting effects of the new $Z^\prime$ boson mediated process, which can be tested in the future. Such models contains three SM singlet RHNs which generate the light neutrino mass through the seesaw mechanism after the U$(1)_X$ breaking. We will also study the prospect of such RHN productions through the Higgs boson at the colliders which can probe a suitable neutrino mass generation mechanism.

Speaker: Arindam Das (Hokkaido University)

ADas_Higgs2021.pdf

ADas_talk_video.mp4

110 Brane-Higgs fields

The problematic huge hierarchy between the usual 4-dimensional Planck mass scale of gravity and the ElectroWeak symmetry breaking scale can interestingly disappear at some point-like location along extra space-like dimensions where the effective gravity scale is reduced down to the TeV scale. Field theories with point-like particle locations (3-dimensional brane-worlds) or point-like interactions deserve special care. In particular it can be shown that, in contrast with usual literature, brane-scalar fields – like the SM Higgs boson – interacting with fermions in the whole space (bulk) do not need to be regularized if rigorous 4- or 5-dimensional treatments are applied: standard regularization introduces a finite width wave function for scalar fields localized along extra dimensions. The variational calculus of least action principle must also be applied strictly to derivate the fermion (Kaluza-Klein) masses and couplings, in particular by distinguishing the natural and essential boundary conditions: the higher-dimensional model – based in particular on extra compact spaces of type interval or circle (orbifold) – must be defined either completely through the action expression [necessity then for new specific brane terms bilinear in the fermion fields] or partially from additional so-called essential boundary conditions. Besides, the correct action integrand definition requires to introduce improper integrals in order to remain compatible with the fermion wave function discontinuities induced by point-like Higgs interactions. Phenomenologically, the correct treatment of the brane-localised Higgs boson could be tested via the precise measurements of the Higgs coupling to di-photon or (flavour-changing) Yukawa interactions at hadron and lepton colliders.

Speaker: gregory moreau

G.Moreau_HiggsCouplings2021.pdf

Talk_Zoom_Gregory-Moreau.mp4

Parallel: Precision and Properties: Live discussion session 3 [Room A]

Parallel A ZOOM Meeting: 683 5990 0577
Passcode: [please register to get this info]

Mattermost channel for discussions: https://mattermost.web.cern.ch/higgs2021/channels/precisions-and-properties

Conveners: Alexander Yohei Huss (CERN), David Sperka (Boston University (US)), Hongtao Yang (Lawrence Berkeley National Lab. (US))

Mattermost discussion

Zoom link A

111 Measurements and interpretations of Simplified Template Cross Sections, differential and fiducial cross sections in Higgs boson decays to two photons with the ATLAS detector

Higgs boson decays to two photons can be selected with high efficiency, and the very good invariant mass resolution allows a robust subtraction of the backgrounds. This talk will present measurements of Simplified Template Cross Sections, differential and fiducial cross sections, as measured in the diphoton decay channel by the ATLAS detector using the full Run 2 dataset of pp collision data collected at 13 TeV at the LHC, and their respective interpretations in the context of an Effective Field Theory.

Speaker: Brianna Stamas (Northern Illinois University (US))

Recording_Stamas_Higgs2021.mp4

Stamas_Higgs2021.pdf

112 Measurements and interpretations of Simplified Template Cross Sections and differential and fiducial cross sections in Higgs boson decays to two W bosons with the ATLAS detector

The Higgs boson decay to two W bosons has the largest bosonic branching fraction and can be used to perform some of the most precise measurements of the Higgs boson production cross sections. This talk will present cross section measurements using pp collision data collected at 13 TeV, including those for the different Higgs boson production processes in the Simplified Template Cross Section framework.

Speaker: Robin Hayes (University of British Columbia (CA))

RobinHayes-HWWxSecAndInterpretations-Higgs2021.pdf

Robin-HWW-talk.mp4

113 Recent results in the H->WW channel at CMS

We present recent results on the cross section measurement of the Higgs boson production using WW decays and the corresponding constraints on the Higgs boson couplings, as well as constraints on new physics models derived from high mass searches. The talk is focused on the recent measurements exploiting the full Run 2 proton-proton collision data collected by the CMS detector.

Speaker: Roberto Seidita (Universita e INFN, Firenze (IT))

higgs_2021_recent_hww_results_CMS.mp4

hww_results_CMS.pdf

114 Measurements of Higgs boson production in decays to two tau leptons with the ATLAS detector

Testing the couplings of the Higgs boson to leptons is important to understand the origin of lepton masses. This talk presents measurements of Higgs boson production in Higgs boson decays to two tau leptons based on pp collision data collected at 13 TeV.

Speaker: Frank Sauerburger (Albert Ludwigs Universitaet Freiburg (DE))

higgs_sauerburger2021-10-21.mp4

higgs_sauerburger2021-10-21.pdf

115 Measurements of Higgs cross sections and differential distributions in the H->tautau final state from CMS

The latest Higgs cross section and differential distribution measurements with CMS data in the H->tautau final state will be discussed.

Speaker: Doyeong Kim (KANSAS STATE UNIVERSITY)

Higgs2021_DoyeongKim.mp4

Higgs2021_DoyeongKim.pdf

116 Combined measurements of Higgs boson production and decays with the ATLAS detector

The most precise measurements of Higgs boson cross sections, using the framework of simplified template cross sections, are obtained from a combination of measurements performed in the different Higgs boson decay channels using pp collision data with a center-of-mass energy of 13 TeV. This talk presents the combined measurements, as well as their interpretations in terms of Higgs coupling modifiers and their ratios, also taking into account results of searches for H->invisible decays as well as off-shell Higgs boson production.

Speaker: Hannah Arnold (CERN)

Arnold_Higgs2021_HComb.pdf

Arnold_Higgs2021_HComb_summary.pdf

Arnold_Higgs2021_recording.mp4

117 Probing the electroweak symmetry breaking with Higgs production at the LHC

The electroweak symmetry breaking (EWSB) mechanism is still an undecided question in particle physics. We propose to utilize the single top quark and Higgs associated production ($th$), $Zh$ production via gluon fusion at the LHC to probe the couplings between the Higgs and the gauge bosons and further to test the EWSB. We demonstrate that the $th$ and $gg\to Zh$ productions are sensitive to the relative sign of couplings ($ht\bar{t}$, $hWW$) and ($ht\bar{t}$, $hZZ$), respectively. We find that the relative sign between $hWW$ and $hZZ$ couplings could be fully determined after combining the present measurements from $gg\to h$, $t\bar{t}h$ and the $th$, $Zh$ channels, as well as $tZj$ and $Zt\bar{t}$ production at the 13 TeV LHC, and this conclusion is not sensitive to the possible new physics contribution induced by $Zt\bar{t}$ couplings in the $gg\to Zh$ production.

Speaker: Dr Bin Yan (Los Alamos National Laboratory)

EWSB_BY.mp4

EWSB_BY.pdf

Parallel: Yukawa: Live discussion session 2 [Room C]

Parallel C ZOOM Meeting: 617 4486 8526
Passcode: [please register to get this info]

Mattermost channel for discussions: https://mattermost.web.cern.ch/higgs2021/channels/yukawa

Conveners: Clara Murgui, Nicolas Morange (Université Paris-Saclay (FR)), Patrick Meade, Stephane Brunet Cooperstein (Univ. of California San Diego (US))

Mattermost discussion

Zoom link C

118 Measurements of ttH production with CMS

We present recent measurements of ttH production with the full run 2 dataset, including measurements of CP properties of the Higgs boson.

Speaker: Sergio Sanchez Cruz (Universitaet Zuerich (CH))

sanchezCruz_higgs2021.pdf

sanchezCruzRecording_v0.mp4

ttHAtHiggs2021_shortVersion.pdf

119 Higgs boson production in association with top quarks with the ATLAS detector

The measurement of Higgs boson production in association with one or two top quarks is essential to understand the top-quark couplings to the Higgs boson. This talk presents the analyses using Higgs boson into several final states, using pp collision data collected at 13 TeV.

Speaker: John Stakely Keller (Carleton University (CA))

Keller_Higgs2021.mp4

Keller_Higgs21.pdf

120 Resurrecting bbh with kinematic shapes

The associated production of a $b\bar{b}$ pair with a Higgs boson could provide an important probe to both the size and the phase of the bottom-quark Yukawa coupling, $y_b$. However, the signal is shrouded by several background processes including the irreducible $Zh, Z\to b\bar{b}$ background. We show that the analysis of kinematic shapes provides us with a concrete prescription for separating the $y_b$-sensitive production modes from both the irreducible and the QCD-QED backgrounds using the $b\bar{b}\gamma\gamma$ final state. We draw a page from game theory and use Shapley values to make Boosted Decision Trees interpretable in terms of kinematic measurables and provide physics insights into the variances in the kinematic shapes of the different channels that help us complete this feat. Adding interpretability to the machine learning algorithm opens up the black-box and allows us to cherry-pick only those kinematic variables that matter most in the analysis. We resurrect the hope of constraining the size and, possibly, the phase of $y_b$ using kinematic shape studies of $b\bar{b}h$ production with the full HL-LHC data and at FCC-hh.

Speaker: Zhuoni Qian (DESY)

Higgs_202110.pdf

Higgs2021.mp4

121 YSF: Analysis of the CP structure of the Higgs boson in tau tau decays at CMS

The standard model (SM) predicts the Higgs boson to be even under charge-parity (CP) inversion. That makes any experimentally observed deviations from this hypothesis an intriguing hint towards new physics.

In this talk we present the first measurement of the CP properties of the Higgs boson in its coupling to leptons. In particular, the decay into a pair of tau leptons preserves CP information via spin correlations of tau decay products. To extract this information, dedicated analysis techniques have been developed and used to analyse data collected by the CMS experiment during Run 2. Altogether, this allowed to measure the mixing angle between CP-even and CP-odd hypotheses with a precision sufficient to reject the pure CP-odd scenario.

Speaker: Oleg Filatov (Deutsches Elektronen-Synchrotron (DE))

CP_HTT_Higgs2021_Filatov.pdf

CP_HTT_Higgs2021_Filatov_video.mp4

122 Higgs boson decay to $J/\psi$ via $c$-quark fragmentation

With the discovery of the Higgs boson at the CERN Large Hadron Collider (LHC), the particle spectrum of the Standard Model (SM) is complete. The next target at the energy frontier will be to study the Higgs properties and to search for the next scale beyond the SM. Experimentally, the $H\to c \bar{c}$ channel would be extremely difficult to dig out because of both the weak Yukawa coupling and the daunting SM di-jet background. We propose to test the charm-quark Yukawa coupling at the LHC and future hadron colliders with the Higgs boson decay to $J/\psi$ via the charm-quark fragmentation. Using the non-relativistic quantum chromodynamics (NRQCD), we study the Higgs decay channel $ H \to c \ \bar{c} + J/\psi $(or $ \eta_c $), where both the color-singlet and color-octet contributions are considered. Our result opens another door to improve determinations at the LHC of the Higgs Yukawa couplings: the final state from this decay mode is quite distinctive with $J/\psi\to e^+e^-,\, \mu^+\mu^-$ and the branching fraction is logarithmically enhanced by the charm-quark fragmentation mechanism.

Speaker: Yang Ma (University of Pittsburgh)

Higgs2021.pdf

zoom_0.mp4

123 Machine learning the Higgs-top CP Measurement

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 provide large CP-sensitivity.

Speaker: Rahool Barman (Oklahoma State University)

CP-tth_Higgs-2021.pdf

CP-tth_Higgs-2021_with_summary.pdf

tth-CP_Higgs2021.mp4

Friday, 22 October

Plenary: Future and closing remarks

Plenary ZOOM Meeting: 995 3901 6069
Passcode: [please register to get this information]
Mattermost channel for discussion for plenary Young Scientist Fora (all days): https://mattermost.web.cern.ch/higgs2021/channels/plenary-ysf-all-days

Mattermost channel for discussions for Monday plenary Opening 1&2 sessions: https://mattermost.web.cern.ch/higgs2021/channels/plenary-mon

Mattermost channel for discussions for Tuesday plenary Properties and Precision sessions: https://mattermost.web.cern.ch/higgs2021/channels/plenary-tue-precision

Mattermost channel for discussions for Tuesday plenary Flavor session: https://mattermost.web.cern.ch/higgs2021/channels/plenary-tue-flavor

Mattermost channel for discussions for Wednesday plenary DiHiggs session: https://mattermost.web.cern.ch/higgs2021/channels/plenary-wed-dihiggs

Mattermost channel for discussions for Wednesday plenary BSM session: https://mattermost.web.cern.ch/higgs2021/channels/plenary-wed-bsm

Mattermost channel for discussions for Thursday plenary EFT session: https://mattermost.web.cern.ch/higgs2021/channels/plenary-thu-eft

Mattermost channel for discussions for Thursday plenary Theory input and experimental tools session: https://mattermost.web.cern.ch/higgs2021/channels/plenary-thu-theoryexp-tools

Mattermost channel for discussions for Friday plenary Future and Closing session: https://mattermost.web.cern.ch/higgs2021/channels/plenary-fri

Convener: Sally Dawson (BNL)

Zoom

Mattermost discussion channels

• Friday Future and Closing (plenary)
• Monday Opening 1&2 (plenary)
• Thursday EFT (plenary)
• Thursday Theory input and experimental tools (plenary)
• Tuesday Flavor (plenary)
• Tuesday Properties and Precision (plenary)
• Wednesday BSM (plenary)
• Wednesday DiHiggs (plenary)
• Young Scientist Fora (all days, plenary)

124 ATLAS+CMS: “Higgs in the light of Run 3, Run 4 and beyond”

Speaker: Marumi Kado (Sapienza Universita e INFN, Roma I (IT))

Higgs2021.pdf

Video Recording

125 “Higgs in the light of future facilities”

Speaker: Isobel Ojalvo (Princeton University (US))

Higgs_in_the_light_of_Future_Colliders.pdf

Video Recording

126 "Vision for using the Higgs”

Speaker: Michelangelo Mangano (CERN)

Mangano_Higgs21.pdf

Video Recording

127 Awards and closing remarks

Speakers: Maria Cepeda (CIEMAT), Michael Duehrssen-Debling (CERN)

Closing remarks.pdf

ConferencePhotoMossaic4.jpeg

Video recording (including intro to Pisa)

128 Higgs Conference 2022

Speaker: Paolo Francavilla (Universita & INFN Pisa (IT))

H2022_Pisa.pdf

Higgs 2022 Pisa