# Preparatory Joint Sessions on "Open questions and News Ideas"

US/Eastern
Description

The Energy Frontier is hosting preparatory joint Topical Group sessions on July 7 and July 8, 2020. The goal of the preparatory joint sessions will be to review ongoing and proposed activities within and across Energy Frontier (EF) Topical  Groups  to identify emerging topics and ideas that will serve as focus points for the physics program of the EF.  These sessions are in preparation for the EF Workshop on July 20-22: they will serve to inform the discussions of the parallel sessions across topical groups during the EF Workshop, and help develop the overall vision of the EF for the Snowmass process.

Zoom Meeting ID: 929 5419 0232

The call for abstracts from the community is now open. We call for two types of contributions:
1. "Short talks" (~10 min duration),  and
2. "Offline flash talks" contributions, which will be viewed offline only. For these offline talks, you are encouraged to submit a few slides, an audio file, or a video file.

During the selection of the abstracts, they may be combined to allow for a short summary talk on related topics. The notifications for selection will be sent shortly after the submission deadline.

• Tuesday, July 7
• EF01+03+04+05+06: Predictions for SM processes ( including higher-order corrections, PDF, parton shower, etc.)

Session convener: Reinhard Schwienhorst

Conveners: Alberto Belloni, Andrey Korytov (University of Florida), Ayres Freitas (University of Pittsburgh), Caterina Vernieri (SLAC), Christophe Royon (The University of Kansas), Doreen Wackeroth (University at Buffalo, SUNY), Huey-Wen Lin (Michigan State University), Junping Tian (University of Tokyo), Michael Begel (Brookhaven National Lab), Michael Schmitt, Pavel Nadolsky (Southern Methodist University), Reinhard Schwienhorst (Michigan State University), Sally Dawson (BNL), Stefan Hoeche (Fermilab)
• 1
The third-generation quarks - from the LHC to the e+e- collider and beyond

I will present a brief review of the role of the top and bottom quarks in an exhaustive characterization of the Standard Model and its possible extensions. The talk will explore the many connections between the top and Higgs/EW sectors and will highlight the qualitatively new information that can be obtained with new installations. I discuss existing work and indicate a few areas where further studies are required.

Speaker: Marcel Vos (IFIC (UVEG/CSIC) Valencia)
• 2
Optimising top-quark pair-production threshold scan at future e+e- colliders

One of the main goals of the future $e^+e^-$ colliders is to measure the top-quark mass and width in a scan of the pair production threshold. Yet, the shape of the threshold cross section depends also on other model parameters as the top Yukawa coupling and the strong coupling constant. We study the expected precision of the top-quark mass determination from the threshold scan at CLIC, ILC and FCC-ee. We use the most general fit approach with all relevant model parameters and expected constraints from earlier measurements taken into account. We demonstrate that even in the most general approach the top-quark mass can be extracted with statistical precision of the order of 20 to 30 MeV. Additional improvement is possible if the running scenario is optimized. We propose the optimisation procedure based on the genetic algorithm. When optimising the mass measurement the statistical uncertainty can be reduced by up to 30%, corresponding to factor of 2 increase in the integrated luminosity. We plan to improve and extend our study by taking into account effects of beam polarisation, including additional observables in the fit (eg. angular distributions) and by more detailed analysis of backgrounds and systematic uncertainties.

Speaker: Kacper Nowak (University of Warsaw)
• 3
Easy e+e- event analysis with LCIO & miniDST

We introduce a new data format tailored to provide an easy and efficient entry into projections for e+e- colliders, called miniDST. The miniDST comprises isolated electron, muon, tau and photon candidates, jets with b- and c-tagging information, particle flow objects and MC truth information as well as event shape variables.
It is based on LCIO and is directly readable in root.
The miniDST can be filled from full detector simulation, SGV fast simulation and from Delphes.
The ILC community is planning to provide substantial data sets at various center-of-mass energies in this format, along with examples and documentation.

• 4
New frontiers in PDF analyses in the HL-LHC era

A robust knowledge of the proton subnuclear structure is a crucial input at the LHC. The uncertainty on the Parton Distribution Functions (PDFs) often represents a limiting factor in the accuracy of theoretical predictions at hadron colliders and this will be even more crucial in the High Luminosity run. I will give an overview of the new exciting challenges that the precision frontier is presenting, such as the simultaneous determination of the parameters entering QCD fits, theoretical uncertainties affecting the predictions entering such fits and the interplay between the proton structure and the hunt for new physics beyond the Standard Model.

Speaker: Maria Ubiali (University of Cambridge)
• 5
High-energy phenomenology implications of the Electron-Ion Collider

With the recent approval of CD-0 for the Electron-Ion Collider and its siting at Brookhaven National Lab, the EIC program enjoys strong forward momentum. As a community, we are now tasked with understanding the phenomenological implications of the future EIC program, which will extend to many corners of particle physics, and planning accordingly to enhance the scientific impact. In this talk, I concentrate on the role the EIC will play in growing the sensitivity of hadron collider-based searches for beyond Standard Model (BSM) physics, as well as other activities at the Energy and Intensity Frontiers. I will highlight recent progress toward the realization of a working community dedicated to maximizing the EIC benefits to efforts at hadron colliders and vice versa.

Speaker: Timothy Hobbs (CTEQ at SMU)
• 6
Precision QCD at future DIS facilities
Speaker: Fredrick Olness (SMU)
• 7
Constraining heavy-flavor PDFs at hadron colliders

We discuss about the possibility of constraining heavy-flavor parton distribution functions (PDFs) in the proton, in particular the top and bottom PDFs. We discuss about heavy-flavor initiated processes and their potential impact in future global PDF analyses.

Speaker: Marco Guzzi (Kennesaw State University)
• 8
Exclusive electroweak processes
Speaker: Cristian Baldenegro Barrera (The University of Kansas (US))
• EF08+09+10+02+07: BSM

Zoom Meeting ID: 929 5419 0232

https://cern.zoom.us/j/92954190232?pwd=RkxvVGRlZWgzZkpoWitSRG1nc1NUQT09

Conveners: Caterina Doglioni (Lund University), Elliot Lipeles (University of Pennsylvania), Isobel Ojalvo (Princeton University (US)), James Hirschauer (Fermi National Accelerator Laboratory), Liantao Wang (University of Chicago), Nausheen Shah (Wayne State University), Patrick Meade (Stony Brook), Simone Pagan Griso (Lawrence Berkeley National Laboratory), Swagato Mukherjee (BNL), Tulika Bose (University of Wisconsin-Madison), Yen-Jie Lee (Massachusetts Institute of Technology), Zhen Liu (University of Maryland)
• 9
Welcome
• 10
Long-lived particle signatures and connections with SUSY and Dark Matter
Speaker: Dr Nishita Desai
• 11
Anomalously charged and Long-lived avatars of BSM physics
Speaker: Prof. James Pinfold
• 12
Searches for milli/fractional/multiple charged particles
Speaker: Matthew Citron (Univ. of California Santa Barbara (US))
• 13
Early kinetic decoupling of dark matter and the Higgs invisible decay in collider experiments

We revisit the Higgs-to-invisible decay ratio in Higgs-portal dark matter models. The Higgs-to-invisible decay searches are powerful probes of the models with increasing sensitivity in upcoming colliders. Close to the mass threshold of a Higgs decay into a pair of DM particles, the coupling value is expected to be very small in order to be compatible with the observed value of the thermal relic abundance. This small coupling perfectly fits with the current status of Higgs-to-invisible constraints and direct detection experiments, such as the XENON1T experiment. At the same time, the small coupling implies a lower DM scattering rate with particles in the early Universe plasma. The suppression of the scattering rate makes the kinetic decoupling happens earlier. Thus, the standard assumption in many relic abundance computations, namely the local thermal equilibrium, is not justified during the freeze-out process. We reanalyze Higgs-portal DM models, such as the Scalar-Singlet and a fermion DM model, taking the new effect of early kinetic decoupling in the relic abundance computation into account. Our results show that a larger value of the DM coupling to the Higgs is allowed. Therefore, current and future Higgs-to-invisible decay searches can generically probe more of the parameter space than previously expected.

Speaker: Dr Tomohiro Abe (Nagoya University)
• 14
New approach to DM searches with mono-photon signature

One of the important goals of the proposed future $e^+e^-$ collider experiments is the search for dark matter particles using different experimental approaches. The most general one is based on the mono-photon signature, which is expected when production of the invisible final state is accompanied by a hard photon from initial state radiation. We propose the procedure of merging the matrix element calculations with the lepton ISR structure function implemented in WHIZARD, which allows for consistent, reliably simulation of mono-photon events for both signal and SM background processes. We demonstrate that cross sections and kinematic distributions of mono-photon in neutrino pair-production events agree very well with corresponding predictions of the KKMC, a Monte Carlo generator providing perturbative predictions for SM and QED processes, which has been widely used in the analysis of LEP data. We plan to exploit the proposed procedure in estimating the sensitivity of future $e^+e^-$ colliders to different DM scenarios. Here we would also like to propose a novel approach, where the experimental sensitivity is defined in terms of both the mediator mass and mediator width. This approach is more model independent than the approaches presented so far, assuming given mediator coupling values to SM and DM particles.

Speaker: Pawel Sopicki (University of Warsaw)
• 15
Signatures of new scalar particles at hadron colliders
Speaker: Tania Robens (Rudjer Boskovic Institute)
• 16
Signatures of new scalar particles at future e+e- colliders

A number of astrophysical observations based on gravitational interactions point to the existence of dark matter (DM) in the Universe, which can not be described with the Standard Model (SM). Many of the proposed extensions of the SM, which can provide a dark matter candidate, involve extended scalar sector and new scalar particles which could be produced at future $e^+e^-$ colliders. We studied the case of the Inert Doublet Model (IDM) in detail, where pair-production of new neutral or charged scalars is possible already at 250 GeV collision energy, and the expected signature is mono-Z or W-pair production (where Z or W can be on- or off-shell, depending on the model parameters) and a large missing energy. For low mass benchmark scenarios, high statistical significance of signal observation is expected for the leptonic signature, while for high scalar masses semi-leptonic final state should be considered, as it provides much higher statistics of signal events. We plan to extend our studies to other models with extended scalar sector, as eg. 2HDM+a model, where new interesting signatures are expected.

Speaker: Aleksander Filip Zarnecki (University of Warsaw)
• 17
Improved (g-2)_mu Measurements and Supersymmetry

The electroweak (EW) sector of the Minimal Supersymmetric Standard Model
(MSSM) can account for variety of experimental data. The lighest
supersymmetric particle (LSP), which we take as the lightest neutralino,
$\tilde \chi_1^0$, can account for the observed Dark Matter (DM)
content of the universe via coannihilation with the next-to-LSP
(NLSP), while being in agreement with negative results from
Direct Detection (DD) experiments. Owing to relatively small production
cross-sections a comparably light EW sector of the MSSM is also in
agreement with
the unsuccessful searches at the LHC. Most importantly, the EW sector of the
MSSM can account for the persistent $3-4\,\sigma$ discrepancy between the
experimental result for the anomalous magnetic moment of the muon, $(g-2)_\mu$, and
its Standard Model (SM) prediction. Under the assumption that the $\tilde\chi_0^1$
provides the full DM relic abundance we first analyze which mass ranges of
neutralinos, charginos and scalar leptons are in agreement with all
experimental data, including relevant LHC searches.
We find an upper limit of $\sim 600$~GeV for
the LSP and NLSP masses.
In a second step we assume that the new result of the
Run~1 of the MUON G-2'' collaboration at Fermilab yields a precision
comparable to the existing experimental result with the same central
value. We analyze the potential impact of the combination of the Run~1 data with the existing \gmin2\ data on the allowed
MSSM parameter space. We find that in this case the upper limits
on the LSP and NLSP masses are substantially reduced by roughly $100$~GeV.
This would yield improved upper limits on these
masses of $\sim 500$~GeV.
In this way, a clear target could be set
for future LHC EW searches, as well as for future high-energy
$e^+e^-$~colliders, such as the ILC or CLIC.

Speaker: Dr Manimala Chakraborti (IFT (UAM/CSIC))
• 18
Current bounds and future prospects of light neutralino dark matter in NMSSM

We examine the region of the parameter space of the Next to Minimal
Supersymmetric Standard Model (NMSSM) with a light neutralino~($M_{\tilde\chi_1^0} \leq~$62.5 GeV) where the SM-like Higgs boson can decay invisibly, the thermal neutralino relic density is smaller than the measured cold dark
matter relic density, and where experimental constraints from LHC searches
and flavor physics are satisfied. We observe allowed regions of parameter space where the lightest neutralino could have a mass as small as $\leq 10~{\rm GeV}$ while still providing a significant component of relic dark matter (DM). We then
examine the prospects for probing the NMSSM with a light neutralino via
direct DM detection searches, via invisible Higgs boson width
experiments at future $e^+e^-$ colliders, via searches for a light
singlet Higgs boson in $2b2\mu$, $2b2\tau$ and $2\mu2\tau$ channels
and via pair production of winos or doublet higgsinos at the high
luminosity LHC and its proposed energy upgrade. For this last-mentioned
electroweakino search, we perform a detailed analysis to map out the
projected reach in the $3l+{\rm E{\!\!\!/}_T}$ channel, assuming that chargino
decays to $W \tilde\chi_1^0$ and the neutralino(s) decay to $Z$ or
$H_{125}$ + $\tilde\chi_1^0$. We find that the HL-LHC can discover SUSY in just part of the parameter space in each of these channels, which together can probe almost the entire parameter space. The HE-LHC probes essentially the entire region with higgsinos~(winos) lighter than 1~TeV~(2~TeV) independently of how the neutralinos decay, and leads to significantly larger signal rates that may allow
further exploration of the underlying new physics.

Speaker: Rahool Kumar Barman (Indian Association for the Cultivation of Science)
• 19
Testing neutrino mass generation mechanism at the electron positron collider

The neutrino oscillation experiment has clearly pointed out that the Standard Model neutrinos have tiny masses and their flavors are mixed. There are a plenty of models which explain the mechanism of the generation of the neutrino mass. In this talk we will discuss about the simple neutrino mass generation process at the TeV scale which is often called the seesaw mechanism and its testability at the high energy colliders.

Speakers: Dr Arindam Das (Osaka University), Arindam Das (KIAS, KNRC, SNU)
• 20
Probing charged lepton number violation via ℓ±ℓ'±W∓W∓

Observed tiny neutrino masses may indicate the existence of new physics including a source of Lepton Number Violation (LNV) at high energies. The effect of such a high-scale physics may be well described by higher dimensional LNV operators. We investigated the dimension-five lepton number violating operator, ℓ±ℓ'±W∓W∓, containing important information on the origin of tiny neutrino masses, which is independent of that from Weinberg operator, and we found that this operator can be probed by current and future experiments, such as neutrinoless double beta decay and high-energy collider experiments. In this talk, I'll show our result and discuss the constraint on the scale of new physics from these experiments. This talk is based on the paper, M. Aoki, K. Enomoto, S. Kanemura, Phys. Rev. D101, 115019 (arXiv:2002.12265[hep-ph]).

Speaker: Kazuki Enomoto (Osaka university)
• Wednesday, July 8
• EF01+02+03+04+07: Higgs, EWK, BSM Higgs
Conveners: Alberto Belloni, Andrey Korytov (University of Florida), Ayres Freitas (University of Pittsburgh), Caterina Vernieri (SLAC), Doreen Wackeroth (University at Buffalo, SUNY), Isobel Ojalvo (Princeton University (US)), Junping Tian (University of Tokyo), Patrick Meade (Stony Brook), Reinhard Schwienhorst (Michigan State University), Sally Dawson (BNL), Swagato Mukherjee (BNL), Yen-Jie Lee (Massachusetts Institute of Technology)
• 21
Positivity Bounds on aQGC
Speakers: Cen Zhang (Brookhaven National Laboratory), Cen Zhang (Institute of High Energy Physics, Chinese Academy Sciences)
• 22
Quantifying the Effects of Beam Polarization on Charged Triple Gauge Couplings
Speaker: Jakob Beyer (DESY)
• 23
LHC/ILC Synergy for Exploration of Extended Higgs Sectors
Speaker: Kei Yagyu (Osaka University)
• 24
Aligned CP-Violating Higgs Model Canceling the Electric Dipole Moment
Speaker: Mitsunori Kubota (Osaka University)
• 25
Triple Higgs Couplings in the 2HDM
Speaker: Francisco Arco
• 26
Higgs Bosons With Large Couplings to Light Quarks
Speaker: Daniel Egana-Ugrinovic (Perimeter Institute)
• 27
Higgs measurements and perspectives at the FCC-hh
Speaker: Michele Selvaggi (UCL- CP3)
• 28
Higgs couplings and VBF at Muon Colliders
Speaker: Luca Mantani (Louvain)
• 29
SMEFT Fits and the Higgs Inverse Problem
Speaker: Samuel Homiller (YITP, Stony Brook)
• 30
Unitarity Bounds on New Physics From Higgs Coupling Measurements
Speakers: Markus Luty (University of California Davis), Spencer Chang (University of Oregon)
• EF05+06+07: QCD (PDF, hadronic structure, heavy ions)
Conveners: Christophe Royon (The University of Kansas), Huey-Wen Lin (Michigan State University), Michael Begel (Brookhaven National Lab), Michael Schmitt, Pavel Nadolsky (Southern Methodist University), Stefan Hoeche (Fermilab), Swagato Mukherjee (BNL), Yen-Jie Lee (Massachusetts Institute of Technology)
• 31
Jet Physics in Relativistic Heavy Ion Collisions and EIC
Speaker: Felix Ringer (Lawrence Berkeley National Laboratory)
• 32
BFKL resummation effects
Speaker: Federico Deganutti
• 33
Small x physics at the LHC, EIC, and FCC
Speakers: Prof. Yuri Kovchegov (The Ohio State University), Yuri Kovchegov (Ohio State University)
• 34
Forward Physics Facility

There is growing interest in the far forward region at the LHC. Detectors placed hundreds of meters downstream from existing interaction points along the beam collision axis may search for LLPs, detect thousands of TeV neutrinos, and make measurements of relevance for a broad range of topics, from hadronic physics to cosmic ray experiments. These efforts are currently limited to fit within existing tunnels, but one could imagine enlarging this space to create a Forward Physics Facility, which would allow more and larger experiments to be placed there, with a huge gain in sensitivity to new physics and standard model studies. In this talk, I would like to propose such a Facility, present some nascent ideas of what it could be good for, and stimulate physicists with a broad range of interests to come together to study the feasibility of creating such a Facility and explore the ways it could expand the existing LHC physics program.

Speaker: Jonathan Feng (UC Irvine)
• 35
Very forward detector: QCD opportunities
Speaker: Prof. Mark Strikman (Penn State University)
• 36
The Future of Heavy Flavor and Exotic Meson Production in RHIC and LHC
Speaker: Xiaojun Yao (Massachusetts Institute of Technology)
• 37
Speaker: Bryan Fulsom (Pacific Northwest National Laboratory)
• 38
Future physics opportunities with W and Z bosons and top quarks for high-density QCD at LHC

Droplets of quark-gluon plasma (QGP), a state of strongly interacting quantum chromodynamics matter, are produced in high-energy collisions between heavy nuclei. Recent theoretical studies suggest using the top quark, the heaviest elementary particle known to date, as a novel time-delayed probe of the QGP. The top quark is a colored particle that decays almost always into a W boson plus a bottom quark, hence by "triggering" on the top quark transverse momentum we can select W bosons produced at different QGP timescales. At variance with most of the experimental signatures considered in the literature so far, where a limiting factor is that they are the integrated result of a fast-evolving and extended medium, top quark thus offers the opportunity to perform a full tomographic analysis of the QGP time evolution.

Using the largest data sample of lead-lead collisions recorded by the Compact Muon Solenoid (CMS) experiment at the unprecedented nucleon-nucleon center-of-mass energy of 5.02 TeV achieved at the Large Hadron Collider (LHC), evidence of top quark pair production is reported. Therefore, for the first time, the feasibility of reconstructing top quark decay products is demonstrated, irrespective of whether interacting with the medium (bottom quarks) or not (leptonically decaying W bosons). This measurement paves the way for more detailed investigations of top quark production in nuclear interactions with increased colliding energies and/or luminosities at current or future higher-energy colliders. In particular, it establishes a new tool for probing nuclear parton distribution functions as well as the properties of the produced QGP.

Speaker: Dr Georgios Konstantinos Krintiras (The University of Kansas (US))
• 39
Dark matter and tau g–2 using the LHC as a photon collider

Electromagnetic fields surrounding LHC beams source high energy photons that can collide to produce new particles. We highlight important and interesting BSM physics targets for QED production from two recent proposals: 1) slepton and dark matter production with proton-tagging using pp beams, 2) new physics modifications to tau g-2 using PbPb beams. These open new cross-cutting opportunities at the energy frontier.

Based on PRL 123 (2019) 14 141801 and 1908.05180

Speaker: Jesse Liu (University of Chicago)
• 40
Discussion