scholarly journals Predictions for the Isolated Prompt Photon Production at the LHC ats= 13 TeV

2017 ◽  
Vol 2017 ◽  
pp. 1-10 ◽  
Author(s):  
Muhammad Goharipour ◽  
Hossein Mehraban
Keyword(s):  
Cross Sections ◽  
Transverse Energy ◽  
Production Cross ◽  
Center Of Mass ◽  
Photon Production ◽  
Prompt Photon ◽  
Center Of Mass Energy ◽  
History Of ◽  
The Impact ◽  
Hadronic Collisions

The prompt photon production in hadronic collisions has a long history of providing information on the substructure of hadrons and testing the perturbative techniques of QCD. Some valuable information about the parton densities in the nucleon and nuclei, especially of the gluon, can also be achieved by analysing the measurements of the prompt photon production cross section whether inclusively or in association with heavy quarks or jets. In this work, we present predictions for the inclusive isolated prompt photon production in pp collisions at center-of-mass energy of 13 TeV using various modern PDF sets. The calculations are presented as a function of both photon transverse energyETγand pseudorapidityηγfor the ATLAS kinematic coverage. We also study in detail the theoretical uncertainty in the cross sections due to the variation of the renormalization, factorization, and fragmentation scales. Moreover, we introduce and calculate the ratios of photon momenta for different rapidity regions and study the impact of various input PDFs on such quantity.

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 Measurements of $${\mathrm{p}} {\mathrm{p}} \rightarrow {\mathrm{Z}} {\mathrm{Z}} $$ production cross sections and constraints on anomalous triple gauge couplings at $$\sqrt{s} = 13\,\text {TeV} $$

2021 ◽  
Vol 81 (3) ◽  
Author(s):  
A. M. Sirunyan ◽  
◽  
A. Tumasyan ◽  
W. Adam ◽  
F. Ambrogi ◽  
...  
Keyword(s):  
Cross Sections ◽  
Invariant Mass Distribution ◽  
Production Cross ◽  
Center Of Mass ◽  
Mass Region ◽  
Proton Proton ◽  
Center Of Mass Energy ◽  
Triple Gauge Couplings ◽  
Theoretical Predictions ◽  
Anomalous Triple Gauge Couplings

AbstractThe production of Z boson pairs in proton–proton ($${\mathrm{p}} {\mathrm{p}} $$ p p ) collisions, $${{\mathrm{p}} {\mathrm{p}} \rightarrow ({\mathrm{Z}}/\gamma ^*)({\mathrm{Z}}/\gamma ^*) \rightarrow 2\ell 2\ell '}$$ p p → ( Z / γ ∗ ) ( Z / γ ∗ ) → 2 ℓ 2 ℓ ′ , where $${\ell ,\ell ' = {\mathrm{e}}}$$ ℓ , ℓ ′ = e or $${{\upmu }}$$ μ , is studied at a center-of-mass energy of 13$$\,\text {TeV}$$ TeV with the CMS detector at the CERN LHC. The data sample corresponds to an integrated luminosity of 137$$\,\text {fb}^{-1}$$ fb - 1 , collected during 2016–2018. The $${\mathrm{Z}} {\mathrm{Z}} $$ Z Z production cross section, $$\sigma _{\text {tot}} ({\mathrm{p}} {\mathrm{p}} \rightarrow {\mathrm{Z}} {\mathrm{Z}} ) = 17.4 \pm 0.3 \,\text {(stat)} \pm 0.5 \,\text {(syst)} \pm 0.4 \,\text {(theo)} \pm 0.3 \,\text {(lumi)} \text { pb} $$ σ tot ( p p → Z Z ) = 17.4 ± 0.3 (stat) ± 0.5 (syst) ± 0.4 (theo) ± 0.3 (lumi) pb , measured for events with two pairs of opposite-sign, same-flavor leptons produced in the mass region $${60< m_{\ell ^+\ell ^-} < 120\,\text {GeV}}$$ 60 < m ℓ + ℓ - < 120 GeV is consistent with standard model predictions. Differential cross sections are also measured and agree with theoretical predictions. The invariant mass distribution of the four-lepton system is used to set limits on anomalous $${\mathrm{Z}} {\mathrm{Z}} {\mathrm{Z}} $$ Z Z Z and $${{\mathrm{Z}} {\mathrm{Z}} \gamma }$$ Z Z γ couplings.

scholarly journals Measurements of angular distance and momentum ratio distributions in three-jet and $${\text {Z}}$$ + two-jet final states in $${\text {p}}{\text {p}}$$ collisions

2021 ◽  
Vol 81 (9) ◽  
Author(s):  
A. M. Sirunyan ◽  
A. Tumasyan ◽  
W. Adam ◽  
T. Bergauer ◽  
M. Dragicevic ◽  
...  
Keyword(s):  
Cross Sections ◽  
Decay Channel ◽  
Production Cross ◽  
Center Of Mass ◽  
Large Angle ◽  
Angular Separation ◽  
Angular Distance ◽  
Proton Proton ◽  
Center Of Mass Energy ◽  
Integrated Luminosity

AbstractCollinear (small-angle) and large-angle, as well as soft and hard radiations are investigated in three-jet and $${\text {Z}}$$ Z  + two-jet events collected in proton-proton collisions at the LHC. The normalized production cross sections are measured as a function of the ratio of transverse momenta of two jets and their angular separation. The measurements in the three-jet and $${\text {Z}}$$ Z  + two-jet events are based on data collected at a center-of-mass energy of 8$$\,{\text {TeV}}$$ TeV , corresponding to an integrated luminosity of 19.8$$\,\text {fb}^{-1}$$ fb - 1 . The $${\text {Z}}$$ Z  + two-jet events are reconstructed in the dimuon decay channel of the $${\text {Z}}$$ Z  boson. The three-jet measurement is extended to include $$\sqrt{s} = 13\,{\text {TeV}} $$ s = 13 TeV data corresponding to an integrated luminosity of 2.3$$\,\text {fb}^{-1}$$ fb - 1 . The results are compared to predictions from event generators that include parton showers, multiple parton interactions, and hadronization. The collinear and soft regions are in general well described by parton showers, whereas the regions of large angular separation are often best described by calculations using higher-order matrix elements.

Trace of nonperturbative charm content of the nucleon on Z + c-jet production

2017 ◽  
Vol 32 (16) ◽  
pp. 1750095
Author(s):  
S. Rostami ◽  
A. Khorramian
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
Center Of Mass ◽  
Distribution Functions ◽  
Mass Energy ◽  
Parton Distribution Functions ◽  
Jet Production ◽  
Center Of Mass Energy ◽  
Intrinsic Charm ◽  
The Impact

We perform a comparison of the impact of different intrinsic charm (IC) models, based on the prediction of the differential cross-sections of [Formula: see text]-boson and [Formula: see text]-jet production in [Formula: see text] collision. It is shown that regardless of choosing the model, considering nonperturbative intrinsic charm component increases the magnitude of the cross-section when the [Formula: see text] transverse momentum grows or at large rapidity [Formula: see text] of the [Formula: see text]. Moreover, to evaluate the effect of different parton distribution functions (PDFs), we also compare the results of two PDF sets in prediction of production [Formula: see text]-jet in [Formula: see text] at a center-of-mass energy of 13 TeV with taking into account the intrinsic charm contribution in the proton. It is shown that the various PDF sets give some difference in the description of the [Formula: see text]-jet cross-section.

scholarly journals Top quark anomalous couplings at the high-luminosity phase of the LHC

2019 ◽  
Vol 34 (18) ◽  
pp. 1950142 ◽  
Author(s):  
Frédéric Déliot ◽  
Miguel C. N. Fiolhais ◽  
António Onofre
Keyword(s):  
Cross Sections ◽  
Top Quark ◽  
W Boson ◽  
Production Cross ◽  
Hadron Collider ◽  
Center Of Mass ◽  
High Luminosity ◽  
Anomalous Couplings ◽  
Center Of Mass Energy ◽  
Single Top

The combination of the latest and most precise measurements of several top quark properties is presented in this paper in order to establish allowed regions on anomalous contributions to the Lorentz structure of the Wtb vertex. These measurements include single top production cross-sections, W boson helicity fractions and forward–backward asymmetries, both at Tevatron and at the Large Hadron Collider (LHC), up to a center-of-mass energy of 13 TeV. The results obtained at 95% Confidence Level (CL) for the top quark anomalous couplings are compared with the limits extracted from a combination that includes the expected measurements at the future High-Luminosity run of the LHC.

scholarly journals Double Charmonium Productions in Electron-Positron Annihilation Using Bethe-Salpeter Approach

2019 ◽  
Vol 2019 ◽  
pp. 1-6
Author(s):  
Hluf Negash ◽  
Shashank Bhatnagar
Keyword(s):  
Positron Annihilation ◽  
Cross Sections ◽  
Production Cross ◽  
Center Of Mass ◽  
Theoretical Models ◽  
Final States ◽  
Charmonium Production ◽  
Center Of Mass Energy ◽  
Electron Positron Annihilation ◽  
Electron Positron

We calculate the double charmonium production cross-section within the framework of 4×4 Bethe-Salpeter Equation in the electron-positron annihilation, at center of mass energy s=10.6GeV, that proceeds through the exchange of a single virtual photon. In this calculation, we make use of the full Dirac structure of 4D BS wave functions of these charmonia, with the incorporation of all the Dirac covariants (both leading and subleading). The calculated cross-sections for the double charmonium productions for final states, (J/Ψ,ηc), (Ψ′,ηc), (J/Ψ,ηc′), and (Ψ′,ηc′), are close to experimental data and in broad agreement with results of other theoretical models.

The Search for Single Top Quark Production in the Muon plus Jets Channel at DØ

2005 ◽  
Vol 20 (14) ◽  
pp. 3190-3192
Author(s):  
◽  
Leonard Christofek
Keyword(s):  
Cross Sections ◽  
Top Quark ◽  
Decay Channel ◽  
Production Cross ◽  
Center Of Mass ◽  
Muon Channel ◽  
Center Of Mass Energy ◽  
Single Top ◽  
Top Quark Production ◽  
Muon Plus Jets

We have performed a search for the electroweak production of single top quarks in [Formula: see text] collisions at the Fermilab Tevatron at a center of mass energy of [Formula: see text]. The search was performed in the muon plus jets decay channel requiring at least one b-tagged jet. The data were collected using the DØ detector between August 2002 and September 2003 corresponding to an integrated luminosity of 158 pb-1. The resulting 95% C.L. upper limits on the production cross sections are 27 pb in the s-channel, 41 pb in the t-channel, and 36 pb in the combined s + t channel using the secondary vertex tagger (SVT) algorithm. We also present results from the combined electron and muon channel search using the DØ detector.

scholarly journals Defiducialization: providing experimental measurements for accurate fixed-order predictions

2020 ◽  
Vol 80 (9) ◽  
Author(s):  
A. Glazov
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
Production Cross ◽  
Vector Boson ◽  
Center Of Mass ◽  
Boson Production ◽  
Center Of Mass Energy ◽  
Full Phase Space ◽  
Theoretical Predictions ◽  
Fixed Order

AbstractAn experimental procedure is proposed to perform measurements of differential cross sections for vector boson production which can be compared to fixed-order QCD predictions with improved accuracy. The procedure relies on applying theoretical acceptance corrections computed as a function of the transverse momentum of the W/Z boson, $$p_T$$ p T , to the experimental measurement, rather than comparing data directly against fiducial fixed-order predictions. It is demonstrated that, contrary to standard fiducial computations, these acceptance factors vary little at low $$p_T$$ p T , so they can be reliably computed using fixed-order perturbation theory. An example analysis is performed using the ATLAS measurement of the Z-boson production cross section at center-of-mass energy of 8 TeV. The resulting full phase space measurement of the cross section differential in the boson rapidity is compared to theoretical predictions computed with next-to-next-to leading-order accuracy in QCD. Further extensions of the approach which include different types of measurements and improved theoretical predictions are discussed.

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