scholarly journals In-medium modification of dijets in PbPb collisions at $$ \sqrt{s_{\mathrm{NN}}} $$ = 5.02 TeV

2021 ◽  
Vol 2021 (5) ◽  
Author(s):  
A. M. Sirunyan ◽  
◽  
A. Tumasyan ◽  
W. Adam ◽  
T. Bergauer ◽  
...  
Keyword(s):  
Charged Particles ◽  
Gluon Plasma ◽  
Angular Distance ◽  
Momentum Balance ◽  
Proton Collision ◽  
High Transverse Momentum ◽  
Proton Proton ◽  
Proton Proton Collision ◽  
Momentum Imbalance ◽  
Proton Proton Collisions

Abstract Modifications to the distribution of charged particles with respect to high transverse momentum (pT) jets passing through a quark-gluon plasma are explored using the CMS detector. Back-to-back dijets are analyzed in lead-lead and proton-proton collisions at $$ \sqrt{s_{\mathrm{NN}}} $$ s NN = 5.02 TeV via correlations of charged particles in bins of relative pseudorapidity and angular distance from the leading and subleading jet axes. In comparing the lead-lead and proton-proton collision results, modifications to the charged-particle relative distance distribution and to the momentum distributions around the jet axis are found to depend on the dijet momentum balance xj , which is the ratio between the subleading and leading jet pT. For events with xj ≈ 1, these modifications are observed for both the leading and subleading jets. However, while subleading jets show significant modifications for events with a larger dijet momentum imbalance, much smaller modifications are found for the leading jets in these events.

The production of charged particles with high transverse momentum in proton-proton collisions at the CERN ISR

1975 ◽  
Vol 87 (1) ◽  
pp. 19-40 ◽  
Author(s):  
B. Alper ◽  
H. Bøggild ◽  
P. Booth ◽  
L.J. Carroll ◽  
G. von Dardel ◽  
...  
Keyword(s):  
Transverse Momentum ◽  
Charged Particles ◽  
High Transverse Momentum ◽  
Proton Proton ◽  
Proton Collisions ◽  
Proton Proton Collisions

scholarly journals Characterization of the topology of proton-proton collisions

2019 ◽  
Author(s):  
Lucas Salgado de Santana ◽  
David Dobrigkeit Chinellato ◽  
Gabriel Reis Garcia
Keyword(s):  
High Energy ◽  
Proton Collision ◽  
Proton Proton ◽  
Particle Correlation ◽  
Proton Collisions ◽  
Proton Proton Collision ◽  
Jet Structure ◽  
Proton Proton Collisions ◽  
Production Mechanisms

In the LHC’s high-energy proton-proton collision experiments, a great amount of particles are produced after the interaction processes. To better understand the production mechanisms of such particles, it is convenient to study and characterize their topology. To do so, we shall study two-particle correlation functions. These functions are calculated with data generated by the PYTHIA event simulator, and in several different intervals of correlated particle’s transverse momentum. In this way, we may observe a particle jet structure, observed in the experiments and previewed by perturbative QCD, and how such structure is affected by different hadronization models.

QCD at Hadron Colliders

2019 ◽  
pp. 199-216
Author(s):  
Michael E. Peskin
Keyword(s):  
High Energy ◽  
Proton Collision ◽  
Hadron Colliders ◽  
Proton Proton ◽  
Proton Collisions ◽  
Jet Production ◽  
Proton Proton Collision ◽  
Proton Proton Collisions

This chapter discusses the properties of proton-proton collision events at high energy and the predictions of QCD. It describes the prediction of jet production in proton-proton collisions and the comparison of this prediction to experiment.

scholarly journals Allen: A High-Level Trigger on GPUs for LHCb

2020 ◽  
Vol 4 (1) ◽  
Author(s):  
R. Aaij ◽  
J. Albrecht ◽  
M. Belous ◽  
P. Billoir ◽  
T. Boettcher ◽  
...  
Keyword(s):  
Pattern Recognition ◽  
High Throughput ◽  
Charged Particles ◽  
Proton Collision ◽  
Collision Rate ◽  
Proton Proton ◽  
Level Trigger ◽  
Lhcb Detector ◽  
Proton Proton Collision ◽  
High Level

AbstractWe describe a fully GPU-based implementation of the first level trigger for the upgrade of the LHCb detector, due to start data taking in 2021. We demonstrate that our implementation, named Allen, can process the 40 Tbit/s data rate of the upgraded LHCb detector and perform a wide variety of pattern recognition tasks. These include finding the trajectories of charged particles, finding proton–proton collision points, identifying particles as hadrons or muons, and finding the displaced decay vertices of long-lived particles. We further demonstrate that Allen can be implemented in around 500 scientific or consumer GPU cards, that it is not I/O bound, and can be operated at the full LHC collision rate of 30 MHz. Allen is the first complete high-throughput GPU trigger proposed for a HEP experiment.

scholarly journals Measurement of the shape of the $$ {B}_s^0\to {D}_s^{\ast -}{\mu}^{+}{\nu}_{\mu } $$ differential decay rate

2020 ◽  
Vol 2020 (12) ◽  
Author(s):  
R. Aaij ◽  
◽  
C. Abellán Beteta ◽  
T. Ackernley ◽  
B. Adeva ◽  
...  
Keyword(s):  
Decay Rate ◽  
Form Factors ◽  
Proton Collision ◽  
Centre Of Mass ◽  
Mass Energy ◽  
Proton Proton ◽  
Lhcb Detector ◽  
Proton Proton Collision ◽  
Integrated Luminosity

Abstract The shape of the $$ {B}_s^0\to {D}_s^{\ast -}{\mu}^{+}{\nu}_{\mu } $$ B s 0 → D s ∗ − μ + ν μ differential decay rate is obtained as a function of the hadron recoil parameter using proton-proton collision data at a centre-of-mass energy of 13 TeV, corresponding to an integrated luminosity of 1.7 fb−1 collected by the LHCb detector. The $$ {B}_s^0\to {D}_s^{\ast -}{\mu}^{+}{\nu}_{\mu } $$ B s 0 → D s ∗ − μ + ν μ decay is reconstructed through the decays $$ {D}_s^{\ast -}\to {D}_s^{-}\gamma $$ D s ∗ − → D s − γ and $$ {D}_s^{-}\to {K}^{-}{K}^{+}{\pi}^{-} $$ D s − → K − K + π − . The differential decay rate is fitted with the Caprini-Lellouch-Neubert (CLN) and Boyd-Grinstein-Lebed (BGL) parametrisations of the form factors, and the relevant quantities for both are extracted.

scholarly journals Multiplicity dependence of (multi-)strange hadron production in proton-proton collisions at $$\sqrt{s}$$ = 13 TeV

2020 ◽  
Vol 80 (2) ◽  
Author(s):  
S. Acharya ◽  
◽  
D. Adamová ◽  
S. P. Adhya ◽  
A. Adler ◽  
...  
Keyword(s):  
Charged Particle ◽  
Charged Particles ◽  
General Purpose ◽  
Particle Multiplicity ◽  
Charged Particle Multiplicity ◽  
Production Rates ◽  
Proton Proton ◽  
Proton Collisions ◽  
Strange Hadron ◽  
Proton Proton Collisions

Abstract The production rates and the transverse momentum distribution of strange hadrons at mid-rapidity ($$\left| y\right| < 0.5$$y<0.5) are measured in proton-proton collisions at $$\sqrt{s}$$s = 13 TeV as a function of the charged particle multiplicity, using the ALICE detector at the LHC. The production rates of $$\mathrm{K}^{0}_{S}$$KS0, $$\Lambda $$Λ, $$\Xi $$Ξ, and $$\Omega $$Ω increase with the multiplicity faster than what is reported for inclusive charged particles. The increase is found to be more pronounced for hadrons with a larger strangeness content. Possible auto-correlations between the charged particles and the strange hadrons are evaluated by measuring the event-activity with charged particle multiplicity estimators covering different pseudorapidity regions. When comparing to lower energy results, the yields of strange hadrons are found to depend only on the mid-rapidity charged particle multiplicity. Several features of the data are reproduced qualitatively by general purpose QCD Monte Carlo models that take into account the effect of densely-packed QCD strings in high multiplicity collisions. However, none of the tested models reproduce the data quantitatively. This work corroborates and extends the ALICE findings on strangeness production in proton-proton collisions at 7 TeV.

scholarly journals A MODEL CONSTRUCTION OF SELF-SIMILARITY BASED DOUBLE PARTON DISTRIBUTION FUNCTIONS FOR PROTON–PROTON COLLISION AT LHC

2013 ◽  
Vol 28 (17) ◽  
pp. 1350079 ◽  
Author(s):  
D. K. CHOUDHURY ◽  
AKBARI JAHAN
Keyword(s):  
Parton Distribution ◽  
Distribution Functions ◽  
Model Construction ◽  
Proton Collision ◽  
Self Similarity ◽  
Parton Distribution Functions ◽  
Proton Proton ◽  
Construction Of Self ◽  
Small X ◽  
Proton Proton Collision

We construct a model for double parton distribution functions (dPDFs) based on the notion of self-similarity, pursued earlier for small x physics at HERA. The most general form of dPDFs contains total 13 parameters to be fitted from data of proton–proton collision at LHC. It is shown that the constructed dPDF does not factorize into two single PDFs in conformity with QCD expectation, and it satisfies the condition that at the kinematic boundary x1+x2 = 1 (where x1 and x2 are the longitudinal fractional momenta of two partons), the dPDF vanishes.

scholarly journals Search for heavy neutral leptons in $$W^+\rightarrow \mu ^{+}\mu ^{\pm }\, \text {jet}$$ decays

2021 ◽  
Vol 81 (3) ◽  
Author(s):  
R. Aaij ◽  
◽  
C. Abellán Beteta ◽  
T. Ackernley ◽  
B. Adeva ◽  
...  
Keyword(s):  
Mass Range ◽  
Lepton Number ◽  
Heavy Neutrino ◽  
Proton Collision ◽  
Final State ◽  
Data Set ◽  
Proton Proton ◽  
Upper Limits ◽  
The Standard Model ◽  
Proton Proton Collision

AbstractA search is performed for heavy neutrinos in the decay of a W boson into two muons and a jet. The data set corresponds to an integrated luminosity of approximately $$3.0\, \text {fb} ^{-1} $$ 3.0 fb - 1 of proton–proton collision data at centre-of-mass energies of 7 and $$8\, \text {TeV} $$ 8 TeV collected with the LHCb experiment. Both same-sign and opposite-sign muons in the final state are considered. Data are found to be consistent with the expected background. Upper limits on the coupling of a heavy neutrino with the Standard Model neutrino are set at $$95\%$$ 95 % confidence level in the heavy-neutrino mass range from 5 to $$50\, \text {GeV/}c^2 $$ 50 GeV/ c 2 . These are of the order of $$10^{-3}$$ 10 - 3 for lepton-number-conserving decays and of the order of $$10^{-4}$$ 10 - 4 for lepton-number-violating heavy-neutrino decays.

Sign in / Sign up

Export Citation Format

Share Document