scholarly journals PRODUCTION OF D AND B MESONS AND THEIR SEMILEPTONIC DECAYS

2011 ◽  
Vol 26 (03n04) ◽  
pp. 549-551
Author(s):  
RAFAŁ MACIUŁA ◽  
ANTONI SZCZUREK ◽  
GABRIELA ŚLIPEK
Keyword(s):  
B Mesons ◽  
Semileptonic Decay ◽  
Good Description ◽  
Semileptonic Decays ◽  
Open Charm ◽  
Factorization Approach ◽  
Proton Proton ◽  
Proton Collisions ◽  
Charged Leptons ◽  
Proton Proton Collisions

We have calculated the kinematical correlations between charged leptons from semileptonic decays of open charm/bottom as well as leptons produced in the Drell-Yan mechanism in proton-proton collisions at BNL RHIC. Presented production rates for open charm and bottom were estimated by a detailed analysis of so-called nonphotonic electrons. The distributions for charm and bottom quarks pairs are calculated in the kt-factorization approach with the help of the Kwieciński unintegrated parton distributions. The hadronization of heavy quarks is done by means of Peterson et al. fragmentation function. The semileptonic decay functions are found by fitting recent semileptonic data obtained by the CLEO and BABAR. We get good description of recent PHENIX data.

scholarly journals Search for physics beyond the standard model in events with jets and two same-sign or at least three charged leptons in proton-proton collisions at $$\sqrt{s}=13\,{\text {TeV}} $$

2020 ◽  
Vol 80 (8) ◽  
Author(s):  
A. M. Sirunyan ◽  
◽  
A. Tumasyan ◽  
W. Adam ◽  
F. Ambrogi ◽  
...  
Keyword(s):  
Standard Model ◽  
Cross Sections ◽  
Center Of Mass ◽  
New Physics ◽  
Beyond The Standard Model ◽  
Proton Proton ◽  
Proton Collisions ◽  
Center Of Mass Energy ◽  
Charged Leptons ◽  
Proton Proton Collisions

Abstract A data sample of events from proton-proton collisions with at least two jets, and two isolated same-sign or three or more charged leptons, is studied in a search for signatures of new physics phenomena. The data correspond to an integrated luminosity of $$137{\,{\text {fb}}^{-1}} $$137fb-1 at a center-of-mass energy of $$13\,{\text {TeV}} $$13TeV, collected in 2016–2018 by the CMS experiment at the LHC. The search is performed using a total of 168 signal regions defined using several kinematic variables. The properties of the events are found to be consistent with the expectations from standard model processes. Exclusion limits at 95% confidence level are set on cross sections for the pair production of gluinos or squarks for various decay scenarios in the context of supersymmetric models conserving or violating R parity. The observed lower mass limits are as large as $$2.1\,{\text {TeV}} $$2.1TeV for gluinos and $$0.9\,{\text {TeV}} $$0.9TeV for top and bottom squarks. To facilitate reinterpretations, model-independent limits are provided in a set of simplified signal regions.

scholarly journals Observation of a $$ {\varLambda}_b^0 $$ − $$ {\overline{\varLambda}}_b^0 $$ production asymmetry in proton-proton collisions at $$ \sqrt{s} $$ = 7 and 8 TeV

2021 ◽  
Vol 2021 (10) ◽  
Author(s):  
◽  
R. Aaij ◽  
A. S. W. Abdelmotteleb ◽  
C. Abellán Beteta ◽  
T. Ackernley ◽  
...  
Keyword(s):  
Semileptonic Decay ◽  
Hadron Production ◽  
Centre Of Mass ◽  
Baryon Production ◽  
Proton Proton ◽  
Proton Collisions ◽  
Standard Deviations ◽  
8 Tev ◽  
Proton Proton Collisions ◽  
Production Asymmetry

Abstract This article presents differential measurements of the asymmetry between $$ {\varLambda}_b^0 $$ Λ b 0 and $$ {\overline{\varLambda}}_b^0 $$ Λ ¯ b 0 baryon production rates in proton-proton collisions at centre-of-mass energies of $$ \sqrt{s} $$ s = 7 and 8 TeV collected with the LHCb experiment, corresponding to an integrated luminosity of 3 fb−1. The $$ {\varLambda}_b^0 $$ Λ b 0 baryons are reconstructed through the inclusive semileptonic decay $$ {\varLambda}_b^0 $$ Λ b 0 → $$ {\varLambda}_c^{+} $$ Λ c + μ−$$ \overline{\nu} $$ ν ¯ μX. The production asymmetry is measured both in intervals of rapidity in the range 2.15 < y < 4.10 and transverse momentum in 2 < pT< 27 GeV/c. The results are found to be incompatible with symmetric production with a significance of 5.8 standard deviations for both $$ \sqrt{s} $$ s = 7 and 8 TeV data, assuming no CP violation in the decay. There is evidence for a trend as a function of rapidity with a significance of 4 standard deviations. Comparisons to predictions from hadronisation models in Pythia and heavy-quark recombination are provided. This result constitutes the first observation of a particle-antiparticle asymmetry in b-hadron production at LHC energies.

scholarly journals Measurement of prompt open-charm production cross sections in proton-proton collisions at $$ \sqrt{s} $$ = 13 TeV

2021 ◽  
Vol 2021 (11) ◽  
Author(s):  
◽  
A. Tumasyan ◽  
W. Adam ◽  
F. Ambrogi ◽  
T. Bergauer ◽  
...  
Keyword(s):  
Cross Sections ◽  
Theoretical Calculations ◽  
Production Cross ◽  
Center Of Mass ◽  
Open Charm ◽  
Charm Mesons ◽  
Proton Proton ◽  
Proton Collisions ◽  
Center Of Mass Energy ◽  
Proton Proton Collisions

Abstract The production cross sections for prompt open-charm mesons in proton-proton collisions at a center-of-mass energy of 13 TeV are reported. The measurement is performed using a data sample collected by the CMS experiment corresponding to an integrated luminosity of 29 nb−1. The differential production cross sections of the D∗±, D±, and D0$$ \left({\overline{\mathrm{D}}}^0\right) $$ D ¯ 0 mesons are presented in ranges of transverse momentum and pseudorapidity 4 < pT< 100 GeV and |η| < 2.1, respectively. The results are compared to several theoretical calculations and to previous measurements.

scholarly journals Search for Heavy Neutral Leptons in Events with Three Charged Leptons in Proton-Proton Collisions at s=13  TeV

2018 ◽  
Vol 120 (22) ◽  
Author(s):  
A. M. Sirunyan ◽  
A. Tumasyan ◽  
W. Adam ◽  
F. Ambrogi ◽  
E. Asilar ◽  
...  
Keyword(s):  
Proton Proton ◽  
Proton Collisions ◽  
Charged Leptons ◽  
Proton Proton Collisions

scholarly journals Evidence for electroweak production of four charged leptons and two jets in proton-proton collisions at s=13TeV

2021 ◽  
Vol 812 ◽  
pp. 135992
Author(s):  
A.M. Sirunyan ◽  
A. Tumasyan ◽  
W. Adam ◽  
F. Ambrogi ◽  
T. Bergauer ◽  
...  
Keyword(s):  
Proton Proton ◽  
Proton Collisions ◽  
Charged Leptons ◽  
Two Jets ◽  
Proton Proton Collisions

scholarly journals PION AND KAON PRODUCTION IN NUCLEON–NUCLEON COLLISIONS

2007 ◽  
Vol 22 (02n03) ◽  
pp. 582-586
Author(s):  
MARTA TICHORUK ◽  
ANTONI SZCZUREK
Keyword(s):  
Degrees Of Freedom ◽  
Inclusive Cross Section ◽  
Nucleon Nucleon ◽  
Distribution Functions ◽  
Parton Distribution Functions ◽  
Kaon Production ◽  
Factorization Approach ◽  
Proton Proton ◽  
Proton Collisions ◽  
Proton Proton Collisions

Inclusive cross section for pion production in proton - proton collisions are calculated based on unintegrated parton distribution functions (uPDFs). In addition to purely gluonic terms the present approach includes also quark degrees of freedom. Phenomenological fragmentation functions from the literature are used. The new mechanisms are responsible for π+ - π- asymmetry. In contrast to standard collinear approach, application of 2 → 1 kt - factorization approach can be extended towards much lower transverse momenta, both at mid and forward rapidity region. The results of the calculation are compared with SPS and RHIC data.

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