Engineering Papers⌕ Search

SEARCH · Engineering Papers

Results for “LHCB”

Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

503 records · Page 28
All sourcesNASA NTRSDOE OSTI
DOE OSTI2012

W Mass results from Tevatron and LHC

Most recent results of W boson mass measurements from Tevatron experiments (CDF and D0) in p{bar p} collisions at {radical}s = 1.96 GeV are reported, using 0.2 fb{sup -1} and 1.0 fb{sup -1} data collected at CDF and D0, respectively. The measurements of W boson properties at LHC experiments (ATLAS, CMS, and LHCb) in pp collisions at {radical}s = 7 TeV, using data collected before Summer 2011, are presented. These measurements are essential at the preparation stage of the W boson mass measurements at LHC. Challenges for W mass measurement at the LHC in comparison with the Tevatron are outlined. Prospects for W mass precision with upcoming measurements and its implications are discussed.

43 PARTICLE ACCELERATORS↗
DOE OSTI2012

Particle Physics in a Season of Change

A digest of the authors opening remarks at the 2011 Hadron Collider Physics Symposium. I have chosen my title to reflect the transitions we are living through, in particle physics overall and in hadron collider physics in particular. Data-taking has ended at the Tevatron, with {approx} 12 fb{sup -1} of {bar p}p interactions delivered to CDF and D0 at {radical}s = 1.96 TeV. The Large Hadron Collider has registered a spectacular first full-year run, with ATLAS and CMS seeing > 5 fb{sup -1}, LHCb recording {approx} 1 fb{sup -1}, and ALICE logging nearly 5 pb{sup -1} of pp data at {radical}s = 7 TeV, plus a healthy dose of Pb-Pb collisions. The transition to a new energy regime and new realms of instantaneous luminosity exceeding 3.5 x 10{sup 33} cm{sup -2} s{sup -1} has brought the advantage of enhanced physics reach and the challenge of pile-up reaching {approx} 15 interactions per beam crossing. I am happy to record that what the experiments have (not) found so far has roused some of my theoretical colleagues from years of complacency and stimulated them to think anew about what the TeV scale might hold. We theorists have had plenty of time to explore many proposals for electroweak symmetry breaking and for new physics that might lie beyond established knowledge. With so many different theoretical inventions in circulation, it is in the nature of things that most will be wrong. Keep in mind that we learn from what experiment tells us is not there, even if it is uncommon to throw a party for ruling something out. Some non-observations may be especially telling: the persistent absence of flavor-changing neutral currents, for example, seems to me more and more an important clue that we have not yet deciphered. It is natural that the search for the avatar of electroweak symmetry breaking preoccupies participants and spectators alike. But it is essential to conceive the physics opportunities before us in their full richness. I would advocate a three-fold approach: Explore, Search, Measure! The first phase of running at the LHC has brought us to two new lands - in proton-proton and lead-lead collisions - and we may well enter other new lands with each change of energy or increase of sensitivity. I believe that it will prove very rewarding to spend some time simply exploring each new landscape, without strong preconceptions, to learn what is there and, perhaps, to encounter interesting surprises. Directed searches, for which we have made extensive preparations, are of self-evident interest. Here the challenge will be to broaden the searches over time, so the searches are not too narrowly directed. Our very successful conception of particles and forces is highly idealized. We have a great opportunity to learn just how comprehensive is our network of understanding by making precise measurements and probing for weak spots, or finding more sweeping accord between theory and experiment.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2012

LCG Persistency Framework (CORAL, COOL, POOL): Status and Outlook

The Persistency Framework consists of three software packages (CORAL, COOL and POOL) addressing the data access requirements of the LHC experiments in different areas. It is the result of the collaboration between the CERN IT Department and the three experiments (ATLAS, CMS and LHCb) that use this software to access their data. POOL is a hybrid technology store for C++ objects, metadata catalogs and collections. CORAL is a relational database abstraction layer with an SQL-free API. COOL provides specific software tools and components for the handling of conditions data. This paper reports on the status and outlook of the project and reviews in detail the usage of each package in the three experiments.

99 GENERAL AND MISCELLANEOUS↗
DOE OSTI2017

$B_s \to K \ell\nu$ Form Factors with 2+1 Flavors

Using the MILC 2+1 flavor asqtad quark action ensembles, we are calculating the form factors $f_0$ and $f_+$ for the semileptonic $B_s \rightarrow K \ell\nu$ decay. A total of six ensembles with lattice spacing from $\approx0.12$ to 0.06 fm are being used. At the coarsest and finest lattice spacings, the light quark mass $m'_l$ is one-tenth the strange quark mass $m'_s$. At the intermediate lattice spacing, the ratio $m'_l/m'_s$ ranges from 0.05 to 0.2. The valence $b$ quark is treated using the Sheikholeslami-Wohlert Wilson-clover action with the Fermilab interpretation. The other valence quarks use the asqtad action. When combined with (future) measurements from the LHCb and Belle II experiments, these calculations will provide an alternate determination of the CKM matrix element $|V_{ub}|$.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2018

Workshop on Pion-Kaon Interactions (PKI2018) Mini-Proceedings

This volume is a short summary of talks given at the PKI2018 Workshop organized to discuss current status and future prospects of pi -K interactions. The precise data on pi K interaction will have a strong impact on strange meson spectroscopy and form factors that are important ingredients in the Dalitz plot analysis of a decays of heavy mesons as well as precision measurement of Vus matrix element and therefore on a test of unitarity in the first raw of the CKM matrix. The workshop has combined the efforts of experimentalists, Lattice QCD, and phenomenology communities. Experimental data relevant to the topic of the workshop were presented from the broad range of different collaborations like CLAS, GlueX, COMPASS, BaBar, BELLE, BESIII, VEPP-2000, and LHCb. One of the main goals of this workshop was to outline a need for a new high intensity and high precision secondary KL beam facility at JLab produced with the 12 GeV electron beam of CEBAF accelerator.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2018

Jet Substructure at the Large Hadron Collider : Experimental Review

Jet substructure has emerged to play a central role at the Large Hadron Collider (LHC), where it has provided numerous innovative new ways to search for new physics and to probe the Standard Model, particularly in extreme regions of phase space. In this article we focus on a review of the development and use of state-of-the-art jet substructure techniques by the ATLAS and CMS experiments. ALICE and LHCb have been probing fragmentation functions since the start of the LHC and have also recently started studying other jet substructure techniques. It is likely that in the near future all LHC collaborations will make significant use of jet substructure and grooming techniques. Much of the work in this field in recent years has been galvanized by the Boost Workshop Series, which continues to inspire fruitful collaborations between experimentalists and theorists. We hope that this review will prove a useful introduction and reference to experimental aspects of jet substructure at the LHC. A companion overview of recent progress in theory and machine learning approaches is given in 1709.04464, the complete review will be submitted to Reviews of Modern Physics.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2018

Fast Reconstruction and Data Scouting

Data scouting, introduced by CMS in 2011, is the use of specialized data streams based on reduced event content, enabling LHC experiments to record unprecedented numbers of proton-proton collision events that would otherwise be rejected by the usual filters. These streams were created to maintain sensitivity to new light resonances decaying to jets or muons, while requiring minimal online and offline resources, and taking advantage of the fast and accurate online reconstruction algorithms of the high-level trigger. The viability of this technique was demonstrated by CMS in 2012, when 18.8 fb$^{-1}$ of collision data at $\sqrt{s} = 8$ TeV were collected and analyzed. For LHC Run 2, CMS, ATLAS, and LHCb implemented or expanded similar reduced-content data streams, promoting the concept to an essential and flexible discovery tool for the LHC.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2018

Opportunities in Flavour Physics at the HL-LHC and HE-LHC

Motivated by the success of the flavour physics programme carried out over the last decade at the Large Hadron Collider (LHC), we characterize in detail the physics potential of its High-Luminosity and High-Energy upgrades in this domain of physics. We document the extraordinary breadth of the HL/HE-LHC programme enabled by a putative Upgrade II of the dedicated flavour physics experiment LHCb and the evolution of the established flavour physics role of the ATLAS and CMS general purpose experiments. We connect the dedicated flavour physics programme to studies of the top quark, Higgs boson, and direct high-$p_T$ searches for new particles and force carriers. We discuss the complementarity of their discovery potential for physics beyond the Standard Model, affirming the necessity to fully exploit the LHC's flavour physics potential throughout its upgrade eras.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2019

Standard Model Physics at the HL-LHC and HE-LHC

The successful operation of the Large Hadron Collider (LHC) and the excellent performance of the ATLAS, CMS, LHCb and ALICE detectors in Run-1 and Run-2 with $pp$ collisions at center-of-mass energies of 7, 8 and 13 TeV as well as the giant leap in precision calculations and modeling of fundamental interactions at hadron colliders have allowed an extraordinary breadth of physics studies including precision measurements of a variety physics processes. The LHC results have so far confirmed the validity of the Standard Model of particle physics up to unprecedented energy scales and with great precision in the sectors of strong and electroweak interactions as well as flavour physics, for instance in top quark physics. The upgrade of the LHC to a High Luminosity phase (HL-LHC) at 14 TeV center-of-mass energy with 3 ab$^{-1}$ of integrated luminosity will probe the Standard Model with even greater precision and will extend the sensitivity to possible anomalies in the Standard Model, thanks to a ten-fold larger data set, upgraded detectors and expected improvements in the theoretical understanding. This document summarises the physics reach of the HL-LHC in the realm of strong and electroweak interactions and top quark physics, and provides a glimpse of the potential of a possible further upgrade of the LHC to a 27 TeV $pp$ collider, the High-Energy LHC (HE-LHC), assumed to accumulate an integrated luminosity of 15 ab$^{-1}$.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2017

Electroweak Precision Measurements with Z Bosons at the LHC

Measurements of the forward-backward asymmetry in the neutral current annihilation process $q\bar{q} \rightarrow Z/\gamma^{*}\rightarrow \ell^{+}\ell^{-}$, where $\ell$ denotes a muon or electron, at the LHC are reported. The forward-backward asymmetry is measured as a function of the dilepton invariant mass yielding the effective weak mixing angle. The effective weak mixing angle values of $\sin^2\theta_{\mathrm{eff}}^{\mathrm{lept}}=0.2308 \pm 0.0012$ and $\sin^2\theta_{\mathrm{eff}}^{\mathrm{lept}}=0.2314 \pm 0.0011$ are obtained by the ATLAS and LHCb collaborations, respectively. The results are in agreement with the current world average.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2014

BSM Higgs boson searches at LHC and the Tevatron

A review of the current experimental results on searches for Higgs bosons in models beyond the Standard Model is presented. Searches from ATLAS, CMS and LHCb use datasets from Run 1 of the LHC, including 7 and 8 TeV proton-proton collisions. Searches from CDF and D0 use the full or partial 1.96 TeV proton-anti-proton collision datasets from the Tevatron.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2021

A general-mass scheme for prompt charm production at hadron colliders

In these proceedings, we apply the recently developed S-ACOT-MPS factorization scheme at the next-to-leading order to prompt charm production at hadron colliders. It provides a good agreement with experimental data on charm meson production measured by LHCb at 7 and 13 TeV. The low-$p_T$ data are on the margins of the theoretical error bands, emphasizing the importance of including contributions beyond the next-to-leading order.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2022

PHENIX Probing QCD Matter Through Heavy Flavor and Quarkonium at RHIC

Recent results from the PHENIX experiment on heavy flavors and quarkonia production in p + Al, p + Au, d + Au, and Au + Au collision systems at psNN = 200 GeV are summarized. The results are carried out by the measurements of the nuclear modification factors and elliptic flow. The nuclear modification factors measurements give insight into the energy loss of heavy quarks in the quark-gluon plasma medium along their path lengths. The elliptic flow measurements are a good tool to investigate the coupling of heavy quarks with the medium. The measurements are presented as a function of centrality, rapidity, and transverse momentum. The interpretations of the results in light of our current theoretical models, and comparison to LHCb and ALICE measurements are presented.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2019

Experiment GlueX: Early results and future plans

The GlueX experiment in Hall D at Jefferson Lab has just finished the data taking for the first phase of the project. The main purpose of the experiment is the search for hybrid mesons in the light quark sector. The experiment studies interactions of a linearly polarized photon beam made by 11.7 GeV electrons with a hydrogen target, with the help of a nearly hermetic spectrometer for charged and neu?tral particles. About 25% of the data acquired have been analyzed. The first physics results include studies of photoproduction of light mesons by a linearly polarized beam, and a measurement of the J/psi photoproduction close to threshold. The latter allows to search for the LHCb s pentaquarks in photoproduction. The first results on the search for hybrid mesons are expected after the whole data sample has been analyzed. The next stage of GlueX data taking will include a new detector for charged kaon identification, and will run at higher luminosity, in order to search for hybrid mesons decaying to strange particles, as well as to contribute to the spectroscopy of hyperons. I will also discuss a proposal to modify the Hall D facility in order to provide a K0L beam, which would allow to study strange baryons and mesons at a new level of precision.

Chudakov, Eugene↗
DOE OSTI2018

Search for Hidden-Charm Pentaquark with CLAS12

LHCb recently announced the discovery of two exotic structures in the J/?+p decay channel, which have been referred to as charmonium-pentaquark states. Resolving differences between models for these states, clarifying the nature of the discovered hidden-charm pentaquark peaks, and discovery of any similar states with other quantum numbers, will require further experimental studies. It is natural to expect that such pentaquark states should be produced in the photoproduction process ?+p-> Pc -> J/?+p, where they will appear as s-channel resonances at photon energy around 10 GeV. The energy and luminosity of the Jefferson Lab CLAS12 photon beam will permit detailed studies of the production and decay properties of such pentaquark resonances. This presentation will discuss a search for these pentaquark states which is currently underway with CLAS12.

Kubarovsky, Valery↗
DOE OSTI2018

Threshold Photoproduction of J/ψ at GlueX

The GlueX experiment at Jefferson Lab uses a 12 GeV electron beam to produce tagged photons via coherent Bremsstrahlung. This linearly-polarized photon beam impinges on a liquid-hydrogen target contained within a hermetic detector with near-complete coverage by drift chambers and electromagnetic calorimeters. The available energy range is ideal to study J/? production close to threshold at 8.2 GeV, and the energy-dependence of the cross-section is very sensitive to the details of the production mechanism. The cross-section is also closely related to the s-channel production of the pentaquark resonances Pc+(4380) and Pc+(4450) observed by LHCb in J/?p systems. Taking advantage of the exclusivity of the reaction and the precise knowledge of the beam energy, the GlueX experiment achieves a fine mass resolution and a pure data sample. We will present preliminary results for the cross-section and an upper limit on the Pc+ ? J/?p branching fraction.

Austregesilo, Alexander↗
DOE OSTI2023

New physics searches at kaon and hyperon factories

Rare meson decays are among the most sensitive probes of both heavy and light new physics. Among them, new physics searches using kaons benefit from their small total decay widths and the availability of very large datasets. On the other hand, useful complementary information is provided by hyperon decay measurements. We summarize the relevant phenomenological models and the status of the searches in a comprehensive list of kaon and hyperon decay channels. We identify new search strategies for under-explored signatures, and demonstrate that the improved sensitivities from current and next-generation experiments could lead to a qualitative leap in the exploration of light dark sectors.

NA62 experiment↗