scholarly journals The production of charged-kaon pairs in proton–antiproton collisions: The role of higher-twist mechanism

2018 ◽  
Vol 33 (28) ◽  
pp. 1850166 ◽  
Author(s):  
M. Demirci ◽  
A. I. Ahmadov
Keyword(s):  
Transverse Momentum ◽  
Pair Production ◽  
Quark Model ◽  
Inclusive Cross Section ◽  
Gluon Fusion ◽  
High Energy ◽  
Light Front ◽  
Charged Kaon ◽  
Proton Antiproton ◽  
Direct Production

The higher-twist (HT) contribution to the charged-kaon pair production in the high energy proton–antiproton collisions at large transverse momentum [Formula: see text] is investigated by using the frozen coupling constant approach for various kaon distribution amplitudes (DAs), which are predicted by light-cone formalism, the light-front quark model, the nonlocal chiral quark model and the light-front holographic AdS/CFT approach. In the numerics, the dependencies of the HT contribution on the transverse momentum [Formula: see text], the rapidity [Formula: see text], and the variable [Formula: see text] are discussed with special emphasis put on DAs. The HT contribution is also compared with the leading-twist ones. It is shown that the HT contributions are dependent on the kaon DAs and also some other phenomenological parameters such as momentum cutoff parameter [Formula: see text]. Inclusive kaon pair production presents a remarkable test case in which HT terms dominate those of LT in certain kinematic regions. The HT direct production process via gluon–gluon fusion contributes significantly to the inclusive cross-section at large [Formula: see text].

scholarly journals Light-front holographic ρ-meson distributions in the momentum space

2021 ◽  
Vol 2021 (1) ◽  
Author(s):  
Satvir Kaur ◽  
Chandan Mondal ◽  
Harleen Dahiya
Keyword(s):  
Transverse Momentum ◽  
Quark Model ◽  
Parton Distribution ◽  
Distribution Functions ◽  
Light Front ◽  
Holographic Model ◽  
Parton Distribution Functions ◽  
Transverse Momentum Dependent ◽  
Quark Spin ◽  
Model Predictions

Abstract We present the leading-twist quark transverse momentum-dependent parton distribution functions (TMDs) for the spin-1 target, such as the ρ-meson, in the light-front framework. Specifically, we predict the TMDs in the light-front holographic model and compare with the light-front quark model predictions. We obtain the TMDs using the overlap of the light-front wave functions. We evaluate the k⊥ moments upto second order and compare with the available theoretical predictions. Further, we analyze the leading-twist parton distribution functions (PDFs) of the ρ-meson in the light-front holographic model which are found to be in accord with the Nambu-Jona-Lasinio (NJL) model and the light-front quark model predictions. We further study the QCD evolution of the PDFs. The positivity bounds on the TMDs and the PDFs are also discussed. We also present the quark spin densities in the transverse momentum plane for different polarization configurations of the quark and the ρ-meson target.

High-energy meson-baryon scattering in a quark model

1974 ◽  
Vol 9 (7) ◽  
pp. 2056-2063 ◽  
Author(s):  
Ramesh Chand
Keyword(s):  
Quark Model ◽  
High Energy

scholarly journals Search for new phenomena in final states with b-jets and missing transverse momentum in $$ \sqrt{\mathrm{s}} $$ = 13 TeV pp collisions with the ATLAS detector

2021 ◽  
Vol 2021 (5) ◽  
Author(s):  
G. Aad ◽  
◽  
B. Abbott ◽  
D. C. Abbott ◽  
A. Abed Abud ◽  
...  
Keyword(s):  
Transverse Momentum ◽  
Pair Production ◽  
Atlas Detector ◽  
Final States ◽  
Proton Proton ◽  
Missing Transverse Momentum ◽  
The Standard Model ◽  
Proton Data ◽  
Identification Techniques ◽  
New Phenomena

Abstract The results of a search for new phenomena in final states with b-jets and missing transverse momentum using 139 fb−1 of proton-proton data collected at a centre-of-mass energy $$ \sqrt{s} $$ s = 13 TeV by the ATLAS detector at the LHC are reported. The analysis targets final states produced by the decay of a pair-produced supersymmetric bottom squark into a bottom quark and a stable neutralino. The analysis also seeks evidence for models of pair production of dark matter particles produced through the decay of a generic scalar or pseudoscalar mediator state in association with a pair of bottom quarks, and models of pair production of scalar third-generation down-type leptoquarks. No significant excess of events over the Standard Model background expectation is observed in any of the signal regions considered by the analysis. Bottom squark masses below 1270 GeV are excluded at 95% confidence level if the neutralino is massless. In the case of nearly mass-degenerate bottom squarks and neutralinos, the use of dedicated secondary-vertex identification techniques permits the exclusion of bottom squarks with masses up to 660 GeV for mass splittings between the squark and the neutralino of 10 GeV. These limits extend substantially beyond the regions of parameter space excluded by similar ATLAS searches performed previously.

scholarly journals High-energy γ -photon polarization in nonlinear Breit-Wheeler pair production and γ polarimetry

2020 ◽  
Vol 2 (3) ◽  
Author(s):  
Feng Wan ◽  
Yu Wang ◽  
Ren-Tong Guo ◽  
Yue-Yue Chen ◽  
Rashid Shaisultanov ◽  
...  
Keyword(s):  
Pair Production ◽  
High Energy ◽  
Photon Polarization
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