2,102 research outputs found
Physics Goals and Experimental Challenges of the Proton-Proton High-Luminosity Operation of the LHC
The completion of Run 1 of the CERN Large Hadron Collider has seen the
discovery of the Higgs boson and an unprecedented number of precise
measurements of the Standard Model, while Run 2 operation has just started to
provide first data at higher energy. Upgrades of the LHC to high luminosity
(HL-LHC) and the experiments (ATLAS, CMS, ALICE and LHCb) will exploit the full
potential of the collider to discover and explore new physics beyond the
Standard Model. In this article, the experimental challenges and the physics
opportunities in proton-proton collisions at the HL-LHC are reviewed
Beam Imaging and Luminosity Calibration
We discuss a method to reconstruct two-dimensional proton bunch densities
using vertex distributions accumulated during LHC beam-beam scans. The -
correlations in the beam shapes are studied and an alternative luminosity
calibration technique is introduced. We demonstrate the method on simulated
beam-beam scans and estimate the uncertainty on the luminosity calibration
associated to the beam-shape reconstruction to be below 1\%.Comment: Figures added, typos correcte
Measuring Higgs Couplings from LHC Data
Following recent ATLAS and CMS publications we interpret the results of their
Higgs searches in terms of Standard Model operators. For a Higgs mass of 125
GeV we determine several Higgs couplings from 2011 data and extrapolate the
results towards different scenarios of LHC running. Even though our analysis is
limited by low statistics we already derive meaningful constraints on modified
Higgs sectors.Comment: 5 pages, 4 figure
Measuring Higgs Couplings at a Linear Collider
Higgs couplings can be measured at a linear collider with high precision. We
estimate the uncertainties of such measurements, including theoretical errors.
Based on these results we show an extrapolation for a combined analysis at a
linear collider and a high-luminosity LHC.Comment: 4 pages, 2 figures; v2: small text clarification, results unchanged,
version to appear in EP
Opportunities and Challenges of Standard Model Production Cross Section Measurements at 8 TeV using CMS Open Data
The CMS Open Data project offers new opportunities to measure cross sections
of standard model (SM) processes which have not been probed so far. In this
work, we evaluate the challenges and the opportunities of the CMS Open Data
project in the view of cross-section measurements. In particular, we reevaluate
SM cross sections of the production of W bosons, Z bosons, top-quark pairs and
WZ dibosons in several decay channels at a center of mass energy of 8 TeV with
a corresponding integrated luminosity of 1.8 fb-1. Those cross sections have
been previously measured by the ATLAS and CMS collaborations and hence can be
used to validate our analysis and calibration strategy. This gives an
indication to which precision also new, so far unmeasured cross sections can be
determined using CMS Open Data by scientists, who are not a member of the LHC
collaborations and hence lack detailed knowledge on experimental and detector
related effects and their handling.Comment: 22 pages, 9 figures. arXiv admin note: text overlap with
arXiv:1904.1119
High Energy Hadron Colliders - Report of the Snowmass 2013 Frontier Capabilities Hadron Collider Study Group
High energy hadron colliders have been the tools for discovery at the highest
mass scales of the energy frontier from the SppS, to the Tevatron and now the
LHC. This report reviews future hadron collider projects from the high
luminosity LHC upgrade to a 100 TeV hadron collider in a large tunnel, the
underlying technology challenges and R&D directions and presents a series of
recommendations for the future development of hadron collider research and
technology.Comment: 28 pages, 18 figures. This document was prepared as the final report
of the Frontier Capabilities Hadron Collider Study Group at the 2013
Community Summer Study "Snowmass 2013", Minneapolis, MN, July-August 201
Future hadron colliders: From physics perspectives to technology R&D
High energy hadron colliders have been instrumental to discoveries in particle physics at the energy frontier and their role as discovery machines will remain unchallenged for the foreseeable future. The full exploitation of the LHC is now the highest priority of the energy frontier collider program. This includes the high luminosity LHC project which is made possible by a successful technology-readiness program for Nb[subscript 3]Sn superconductor and magnet engineering based on long-term high-field magnet R&D programs. These programs open the path towards collisions with luminosity of 5Ă10[superscript 34] cm[superscript â2] s[superscript â1] and represents the foundation to consider future proton colliders of higher energies. This paper discusses physics requirements, experimental conditions, technological aspects and design challenges for the development towards proton colliders of increasing energy and luminosity
CMS computing operations during run 1
During the first run, CMS collected and processed more than 10B data events and simulated more than 15B events. Up to 100k processor cores were used simultaneously and 100PB of storage was managed. Each month petabytes of data were moved and hundreds of users accessed data samples. In this document we discuss the operational experience from this first run. We present the workflows and data flows that were executed, and we discuss the tools and services developed, and the operations and shift models used to sustain the system. Many techniques were followed from the original computing planning, but some were reactions to difficulties and opportunities. We also address the lessons learned from an operational perspective, and how this is shaping our thoughts for 2015
Prospective Studies for LEP3 with the CMS Detector
On July 4, 2012, the discovery of a new boson, with mass around 125 GeV/c2
and with properties compatible with those of a standard-model Higgs boson, was
announced at CERN. In this context, a high-luminosity electron-positron
collider ring, operating in the LHC tunnel at a centre-of-mass energy of 240
GeV and called LEP3, becomes an attractive opportunity both from financial and
scientific point of views. The performance and the suitability of the CMS
detector are evaluated, with emphasis on an accurate measurement of the Higgs
boson properties. The precision expected for the Higgs boson couplings is found
to be significantly better than that predicted by Linear Collider studies.Comment: 25 pages, 13 figures, 3 tables, Submitted to the European Strategy
Preparatory Group (contribution 171), Companion to arXiV:1208.0504. Version 2
contains several additional Higgs decay channels studied, and numbers for
TLEP as well as for LEP
DELight: a Direct search Experiment for Light dark matter with superfluid helium
To reach ultra-low detection thresholds necessary to probe unprecedentedly
low Dark Matter masses, target material alternatives and novel detector designs
are essential. One such target material is superfluid He which has the
potential to probe so far uncharted light Dark Matter parameter space at
sub-GeV masses. The new ``Direct search Experiment for Light dark matter'',
DELight, will be using superfluid helium as active target, instrumented with
magnetic micro-calorimeters. It is being designed to reach sensitivity to
masses well below 100\,MeV in Dark Matter-nucleus scattering interactions.Comment: IDM2022 proceedings submitted to SciPos
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