A5063304545- Particle physics theoretical and experimental studies
- Dark Matter and Cosmic Phenomena
- Quantum Chromodynamics and Particle Interactions
- High-Energy Particle Collisions Research
- Particle Detector Development and Performance
- Distributed and Parallel Computing Systems
- Cosmology and Gravitation Theories
- Neutrino Physics Research
- Black Holes and Theoretical Physics
- Mathematics, Computing, and Information Processing
- Simulation Techniques and Applications
- Astrophysics and Cosmic Phenomena
- Computational Physics and Python Applications
- Superconducting Materials and Applications
- Cold Atom Physics and Bose-Einstein Condensates
- Medical Imaging Techniques and Applications
- Pulsars and Gravitational Waves Research
- Nuclear physics research studies
- Gamma-ray bursts and supernovae
- Scientific Computing and Data Management
- Nuclear Physics and Applications
- Advanced Differential Geometry Research
- Scientific Research and Discoveries
- Physics of Superconductivity and Magnetism
- International Science and Diplomacy
California Institute of Technology
2020-2025
University of Bonn
2017-2022
Lawrence Berkeley National Laboratory
2008-2020
University of California, Berkeley
2007-2020
European Organization for Nuclear Research
2012-2019
University of Michigan–Ann Arbor
2013-2014
University of California System
2012
Institute for Advanced Study
2008-2010
Scuola Normale Superiore
2002-2005
Berkeley College
2004
The first 1/fb of LHC searches have set impressive limits on new colored particles decaying to missing energy. We address the implication these for naturalness in supersymmetry (SUSY). General bottom-up considerations natural electroweak symmetry breaking show that higgsinos, stops, and gluino should not be too far above weak scale. rest spectrum, including squarks two generations, can heavier beyond current reach. used collider simulations determine all pose gluino. find stops left-handed...
This document proposes a collection of simplified models relevant to the design new-physics searches at LHC and characterization their results. Both ATLAS CMS have already presented some results in terms models, we encourage them continue expand this effort, which supplements both signature-based benchmark model interpretations. A is defined by an effective Lagrangian describing interactions small number new particles. Simplified can equally well be described masses cross-sections. These...
This document is the final report of ATLAS-CMS Dark Matter Forum, a forum organized by ATLAS and CMS collaborations with participation experts on theories Matter, to select minimal basis set dark matter simplified models that should support design early LHC Run-2 searches. A prioritized, compact benchmark proposed, accompanied studies parameter space these repository generator implementations. also addresses how apply Effective Field Theory formalism for collider searches present results...
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 $B$...
The measured $\bar{B}\to D^{(*)} l \bar\nu$ decay rates for light leptons ($l=e,\mu$) constrain all D^{(*)}$ semileptonic form factors, by including both the leading and ${\cal O}(\Lambda_{\text{QCD}}/m_{c,b})$ subleading Isgur-Wise functions in heavy quark effective theory. We perform a novel combined fit to distributions predict $\bar{B} \to \tau\bar\nu$ determine CKM matrix element $|V_{cb}|$. Most theoretical experimental papers have neglected uncertainties predictions factor ratios at...
This document a outlines set of simplified models for dark matter and its interactions with Standard Model particles. It is intended to summarize the main characteristics that these have when applied searches at LHC, provide number useful expressions reference. The list includes both s-channel t-channel scenarios. For s-channel, spin-0 spin-1 mediations are discussed, also realizations where Higgs particle provides portal between visible sectors. guiding principles underpinning proposed...
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.
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 investigate the direct and indirect bounds on dipole operators involving top quark. A careful analysis shows that experimental upper limit neutron electric moment strongly constrains chromo-electric of top. improve previous by 2 orders magnitude. This has significant implications for new physics models it also means $CP$ violation in pair production mediated will not be accessible at LHC. The conserving chromo-magnetic moments are constrained recent measurements $t\overline{t}$ spectrum...
Fastlim is a tool to calculate conservative limits on extensions of the Standard Model from direct LHC searches without performing any Monte Carlo event generation. The program reconstructs visible cross sections (cross after selection cuts) pre-calculated efficiency tables and section for simplified topologies. As proof concept approach, we have implemented relevant supersymmetric models with R-parity conservation. takes spectrum coupling information given model point provides, each signal...
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...
We explore models for the GeV Galactic Center excess (GCE) observed by Fermi Telescope, focusing on $\ensuremath{\chi}\ensuremath{\chi}\ensuremath{\rightarrow}f\overline{f}$ annihilation processes in ${Z}_{3}$ next-to-minimal supersymmetric standard model (NMSSM). begin examining requirements a simplified [parametrized couplings and masses of dark matter (DM) mediator particles] to reproduce GCE via $\ensuremath{\chi}\ensuremath{\chi}\ensuremath{\rightarrow}f\overline{f}$, while...
We analyze the significant new model independent constraints on extensions of standard (SM) that follow from recent measurements B^0_s-\bar B^0_s mass difference. The time-dependent CP asymmetry in B_s -> \psi\phi, S_{\psi\phi}, will be measured with good precision first year LHC data taking, which further constrain parameter space many SM, particular, next-to-minimal flavor violation. semileptonic decay, A_{SL}^s, is also important to these frameworks, and could give clues our understanding...
We derive robust model-independent bounds on DM annihilations and decays from the first year of FERMI gamma-ray observations whole sky. These only have a mild dependence density profile allow following interpretations PAMELA electron/positron excesses: primary channels mu+ mu-, mu-mu+mu- or e+ e- e-. An isothermal-like is needed for annihilating DM. In all such cases, gamma spectra must contain significant component, that may be probed in future.
Monojet searches using Effective Field Theory (EFT) operators are usually interpreted as a robust and model independent constraint on direct detection (DD) scattering cross-sections. At the same time, mediator particle must be present to produce dark matter (DM) at LHC. This may produced shell, so that for mediating can constrain effective operator being applied monojet constraints. In this first paper, we do case study t-channel models in searches, where (Standard Model singlet) DM is pair...
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 estimate, in a large class of scenarios, the sensitivity to new physics ${B}_{d}$ and ${B}_{s}$ mixings achievable with $50\text{ }\text{ }{\mathrm{ab}}^{\ensuremath{-}1}$ Belle II }{\mathrm{fb}}^{\ensuremath{-}1}$ LHCb data. find that current limits on contributions both ${B}_{d,s}$ systems can be improved by factor $\ensuremath{\sim}5$ for all values $CP$-violating phases, corresponding over 2 increase scale probed. Assuming same suppressions Cabbibo-Kobayashi-Maskawa matrix elements as...