A5062379310- Particle physics theoretical and experimental studies
- Dark Matter and Cosmic Phenomena
- Particle Detector Development and Performance
- High-Energy Particle Collisions Research
- Atomic and Subatomic Physics Research
- Black Holes and Theoretical Physics
- Distributed and Parallel Computing Systems
- Cosmology and Gravitation Theories
- Simulation Techniques and Applications
- Mathematics, Computing, and Information Processing
- Computational Physics and Python Applications
- Quantum Chromodynamics and Particle Interactions
- Noncommutative and Quantum Gravity Theories
- Advanced Semiconductor Detectors and Materials
- Quantum, superfluid, helium dynamics
- Neutrino Physics Research
- International Science and Diplomacy
- Radiation Detection and Scintillator Technologies
- Climate Change Communication and Perception
- Cold Atom Physics and Bose-Einstein Condensates
- Scientific Computing and Data Management
- Astrophysics and Cosmic Phenomena
- Quantum and electron transport phenomena
- Advanced Thermodynamics and Statistical Mechanics
- Spaceflight effects on biology
Lawrence Berkeley National Laboratory
2015-2025
University of California System
2014-2025
University of California, Berkeley
2015-2023
European Organization for Nuclear Research
2020-2022
Institute for Advanced Study
2019-2021
Center for Theoretical Biological Physics
2016-2017
Kavli Institute for the Physics and Mathematics of the Universe
2016
The University of Tokyo
2016
Rutgers, The State University of New Jersey
2011-2015
KU Leuven
2010
We study the direct detection prospects for a representative set of simplified models sub-GeV dark matter (DM), accounting existing terrestrial, astrophysical and cosmological constraints. focus on lighter than an MeV, where these constraints are most stringent, find three scenarios with accessible cross sections: (i) DM interacting via ultralight kinetically mixed photon, (ii) sub-component nucleons or electrons through light scalar vector mediator, (iii) coupled mediator heavier ~ 100 keV.
We advocate for the construction of a new detector element at LHCb experiment, designed to search displaced decays beyond Standard Model long-lived particles, taking advantage large shielded space in cavern that is expected soon become available. discuss general features and putative capabilities such an as well its various advantages complementarities with respect existing LHC experiments proposals SHiP MATHUSLA. For two well-motivated benchmark scenarios---Higgs decay dark photons $B$...
Abstract The Physics Beyond Colliders initiative is an exploratory study aimed at exploiting the full scientific potential of CERN’s accelerator complex and infrastructures through projects complementary to LHC other possible future colliders. These will target fundamental physics questions in modern particle physics. This document presents status proposals presented framework Standard Model working group, explore their reach impact that CERN could have next 10–20 years on international landscape.
Abstract With the establishment and maturation of experimental programs searching for new physics with sizeable couplings at LHC, there is an increasing interest in broader particle astrophysics community exploring light feebly-interacting particles as a paradigm complementary to New Physics sector TeV scale beyond. FIPs 2020 has been first workshop fully dedicated was held virtually from 31 August 4 September 2020. The gathered together experts collider, beam dump, fixed target experiments,...
We show that ultraperipheral heavy-ion collisions at the Large Hadron Collider (LHC) can be used to search for axionlike particles with mass below 100 GeV. The Z^{4} enhanced photon-photon luminosity from ions provides a large exclusive production rate, signature of resonant pair back-to-back photons and no other activity in detector. In addition, we present both new updated limits recasting multiphoton searches LEP II LHC, which are more stringent than those currently literature range MeV
We consider models for the di-photon resonance observed at ATLAS (with 3.6 fb^{-1}) and CMS 2.6 fb^{-1}). find there is no conflict between signal reported 13 TeV, constraints from both experiments 8 TeV with 20.3 fb^{-1}. make a simple argument why adding only one new to standard model (SM) not sufficient explain observation. explore four viable options: (i): production decay through loops of messenger fermions or scalars; (ii): resonant which decays + X; (iii): an edge configuration where...
We examine the theoretical motivations for long-lived particle (LLP) signals at LHC in a comprehensive survey of Standard Model (SM) extensions. LLPs are common prediction wide range theories that address unsolved fundamental mysteries such as naturalness, dark matter, baryogenesis and neutrino masses, represent natural generic possibility physics beyond SM (BSM). In most cases LLP lifetime can be treated free parameter from $\mu$m scale up to Big Bang Nucleosynthesis limit $\sim 10^7$m....
Particles beyond the Standard Model (SM) can generically have lifetimes that are long compared to SM particles at weak scale. When produced experiments such as Large Hadron Collider (LHC) CERN, these long-lived (LLPs) decay far from interaction vertex of primary proton-proton collision. Such LLP signatures distinct those promptly decaying targeted by majority searches for new physics LHC, often requiring customized techniques identify, example, significantly displaced vertices, tracks with...
We show that polar materials are excellent targets for direct detection of sub-GeV dark matter due to the presence gapped optical phonons as well acoustic with high sound speed. take example Gallium Arsenide (GaAs), which has properties needed experimental realization, and where many results can be estimated analytically. find GaAs reach photon absorption, completely cover freeze-in benchmark scattering via an ultralight photon, is competitive other proposals detect sub-MeV off nuclei.
We consider the direct detection of dark matter (DM) with polar materials, where single production optical or acoustic phonons gives excellent reach to scattering sub-MeV DM for both scalar and vector mediators. Using Density Functional Theory (DFT), we calculate material-specific matrix elements, focusing on GaAs sapphire, show that in an anisotropic crystal such as sapphire features a strong directional dependence. For example, candidate mass 40 keV relic abundance set by freeze-in, daily...
We present a general class of natural theories in which the Higgs is pseudo-goldstone boson an orbifolded gauge theory. The symmetry protecting at low energies accidental global quadratic action, rather than full continuous symmetry. lightest degrees freedom weak scale carry no Standard Model (SM) quantum numbers and interact with visible matter principally through portal. find that twin simplest example orbifold Higgs. This opens door to systematic study "neutral naturalness": SM-neutral...
Light dark matter searches require new experimental approaches compared to the well-established nuclear-recoil techniques now in use. In this paper, authors consider potential detect sub-MeV via multi-excitation modes superfluid helium.
Abstract This document presents the physics case and ancillary studies for proposed CODEX-b long-lived particle (LLP) detector, as well a smaller proof-of-concept demonstrator CODEX- $$\beta $$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mi>β</mml:mi> </mml:math> , to be operated during Run 3 of LHC. Our development synthesizes ‘top-down’ ‘bottom-up’ theoretical approaches, providing detailed survey both minimal complete models featuring LLPs. Several these have not been...
When a nucleus in an atom undergoes collision, there is small probability of electron being excited inelastically as result the Migdal effect. In this Letter, we present first complete derivation effect from dark matter-nucleus scattering semiconductors, which also accounts for multiphonon production. The rate can be expressed terms energy loss function material, calculate with density functional theory methods. Because smaller gap excitations, find that much higher semiconductors than...
We present DarkELF, a python package to calculate interaction rates of light dark matter in dielectric materials, including screening effects. The full response the material is parametrized terms energy loss function (ELF) material, which DarkELF converts into differential scattering for both direct electron and through Migdal effect. In addition, can rate produce phonons from sub-MeV via photon mediator, as well absorption comprised photons. includes precomputed ELFs Al,...
We provide five benchmark hidden valley models with perturbative parton showers, which span a wide range of dark shower phenomenology. consider production through an $s$-channel, heavy mediator, can be identified the SM Higgs. By assuming set well-motivated decay portals, one moreover fix both branching ratios mesons and lower bound on their lifetime. public python tool used to generate self-consistent PYTHIA 8 cards for our models.
A number of direct detection experiments are searching for electron excitations created by scattering sub-GeV dark matter. We present an alternate formulation matter-electron in terms the dielectric response a material. For matter which couples to electrons, this approach automatically accounts in-medium screening effects, were not included previous rate calculations semiconductor targets. show that effects appear both scalar and vector mediators. The result is non-negligible reduction reach...
Very high multiplicity, spherically-symmetric distributions of soft particles, with p T ∼ few×100 MeV, may be a signature strongly-coupled hidden valleys that exhibit long, efficient showering windows. With traditional triggers, such 'soft bomb' events closely resemble pile-up and are therefore only recorded minimum bias triggers at very low efficiency. We demonstrate proof-of-concept for high-level triggering strategy efficiently separates bombs from by searching 'belt fire': density band...
Run 5 of the high-luminosity LHC era (and beyond) may provide new opportunities to search for physics beyond standard model at interaction point 2. In particular, taking advantage existing ALICE detector and infrastructure provides an opportunity displaced decays long-lived particles. While this proposal well be preempted by ongoing goals, examination its potential reach a compelling comparison with respect other particle proposals. full event reconstruction identification could possible...
We introduce and systematically study an expansive class of “orbifold Higgs” theories in which the weak scale is protected by accidental symmetries arising from orbifold reduction continuous symmetries. The protection mechanism eliminates quadratic sensitivity Higgs mass to higher scales at one loop (or more) does not involve any new states charged under Standard Model. structures top sectors are universal determined exclusively group theoretical considerations. twin model fits within our...
In this work, we consider the case of a strongly coupled dark/hidden sector, which extends Standard Model (SM) by adding an additional non-Abelian gauge group. These extensions generally contain matter fields, much like SM quarks, and fields similar to gluons. We focus on exploration such sectors where dark particles are produced at LHC through portal undergo rapid hadronization within sector before decaying back, least in part potentially with sizeable lifetimes, particles, giving range...
A bstract We study the sensitivity of existing MEG data to lepton flavor violating axion-like particles produced through μ + → e aγ and estimate discovery potential for upcoming II experiment in this channel. The signal efficiency can be improved significantly if a new trigger implemented dedicated run with reduced beam intensity. This search would establish world leading measurement channel only 1 month taking.