scholarly journals Z plus jets production via double parton scattering in pA collisions at the LHC

2020 ◽  
Vol 80 (8) ◽  
Author(s):  
Boris Blok ◽  
Federico Alberto Ceccopieri

Abstract We present results on Zjj production via double parton scattering in pA collisions at the LHC. We perform the analysis at leading and next-leading order accuracy with different sets of cuts on jet transverse momenta and accounting for the single parton scattering background. By exploiting the experimental capability to measure the centrality dependence of the cross section, we discuss the feasibility of DPS observation in already collected data at the LHC and in future runs.

2019 ◽  
Vol 2019 ◽  
pp. 1-9 ◽  
Author(s):  
Jonathan R. Gaunt ◽  
Tomas Kasemets

In this review, we describe the status of transverse momentum dependence (TMD) in double parton scattering (DPS). The different regions of TMD DPS are discussed, and expressions are given for the DPS cross section contributions that make use of as much perturbative information as possible. The regions are then combined with each other as well as single parton scattering to obtain a complete expression for the cross section. Particular emphasis is put on the differences and similarities to transverse momentum dependence in single parton scattering. We further discuss the status of the factorisation proof for double colour singlet production in DPS, which is now on a similar footing to the proofs for TMD factorisation in single Drell-Yan, discuss parton correlations, and give an outlook on possible research on DPS in the near future.


2016 ◽  
Vol 752 ◽  
pp. 40-45 ◽  
Author(s):  
Matteo Rinaldi ◽  
Sergio Scopetta ◽  
Marco Traini ◽  
Vicente Vento

2020 ◽  
Vol 80 (8) ◽  
Author(s):  
Edgar Huayra ◽  
Emmanuel G. de Oliveira ◽  
Roman Pasechnik

Abstract We discuss the associated $$c\bar{c}$$cc¯ and $$b\bar{b}$$bb¯ quark pairs production in the double-parton scattering (DPS) process in ultraperipheral (UPCs) AA collisions. We derive an analogue of the inclusive DPS pocket formula and the photon-energy dependent effective cross section considering an overlap between the hard SPS scatterings. We provide numerical predictions for the DPS cross sections for the $$c\bar{c}b\bar{b}$$cc¯bb¯ production process at the typical energies of AA UPCs at the LHC and FCC colliders and also characterize the A dependence of the total UPC DPS cross section.


2014 ◽  
Vol 29 (07) ◽  
pp. 1450049 ◽  
Author(s):  
H. Saveetha ◽  
D. Indumathi ◽  
Subhadip Mitra

A detailed study of fragmentation of vector mesons at the next-to-leading order (NLO) in QCD is given for e+e- scattering. A model with broken SU(3) symmetry using three input fragmentation functions α(x, Q2), β(x, Q2) and γ(x, Q2) and a strangeness suppression parameter λ describes all the light quark fragmentation functions for the entire vector meson octet. At a starting low energy scale of [Formula: see text] for three light quarks (u, d, s) along with initial parametrization, the fragmentation functions are evolved through DGLAP evolution equations at NLO and the cross-section is calculated. The heavy quarks contribution are added in appropriate thresholds during evolution. The results obtained are fitted at the momentum scale of [Formula: see text] for LEP and SLD data. Good-quality fits are obtained for ρ, K*, ω and ϕ mesons, implying the consistency and efficiency of this model. Strangeness suppression in this model is understood both in terms of ratios of quark fragmentation functions alone as well as in terms of observables; the latter yield a suppression through the K*/ρ multiplicity ratio of about 0.23 while the x dependence of this suppression is also parametrized through the cross-section ratios.


2007 ◽  
Vol 22 (02n03) ◽  
pp. 591-595 ◽  
Author(s):  
VADIM LENSKY ◽  
JOHANN HAIDENBAUER ◽  
CHRISTOPH HANHART ◽  
VADIM BARU ◽  
ALEXANDER KUDRYAVTSEV ◽  
...  

We study the production amplitude for the reaction NN → NNπ up to next-to-leading order in chiral perturbation theory. We show that the irreducible chiral loops at this order exactly cancel those terms that arise from the off-shell parts of the πN rescattering vertex. This cancellation is required for formal consistency of the whole scheme. The net effect of the inclusion of all next-to-leading order loops is to enhance the leading rescattering amplitude by a factor of 4/3 compared to phenomenological studies, bringing its contribution to the cross section for pp → dπ+ close to the experimental value.


2012 ◽  
Vol 90 (1) ◽  
pp. 25-37 ◽  
Author(s):  
A. Sepehri ◽  
M.E. Zomorrodian ◽  
A. Moradi Marjaneh ◽  
P. Eslami ◽  
S. Shoorvazi

In curved space–time near TeV black holes many gluons and quarks produced by the Unruh effect interact with each other and create Higgs bosons. We study the Unruh effect and show that, for gluons and quarks, the internal stationary state of a Schwarzschild black hole can be represented by a maximally entangled two-mode squeezed state of outgoing and infalling Hawking radiation. We consider different channels for Higgs boson production near event horizons of mini black holes at the Large Hadron Collider (LHC) and obtain the cross section in each channel. We observe that the cross section of a Higgs boson produced via gluon fusion near a single black hole is much larger for smaller black hole masses. This is because the temperature of the black hole becomes larger as the mass becomes smaller and the thermal radiation of the gluons is enhanced. At lower mass, MBH < 4 TeV, the black hole will not be able to emit Higgs, but will still be able to produce a quark; for MBH < 3 TeV the black hole can only emit massless gluons. We show that as the black hole mass at the LHC increases (4 TeV < MBH < 8 TeV) most of the Higgs boson production is due to the Unruh effect near the event horizon of the black hole. Comparing these Higgs boson cross sections with Higgs boson cross sections in perturbative quantum chromodynamics, we find that micro black holes can be a source of Higgs production at the LHC. Finally, we calculate the effects of Higgs boson radiation due to mini black holes on the hadronic cross section at the LHC. We observe that as the order of perturbation theory increases this effect becomes systematically more significant because at higher orders there exist more channels for Higgs production and, in our calculations, Higgs decay into massive quark–antiquark pairs. At smaller masses, MBH < 2 TeV, the hadronic cross section at leading order is large while the cross sections at next-to-leading order and at next-to-next-to-leading order are rising at MBH ∼ 2 and 3 TeV, respectively, and exhibit a turn-over at moderate values of black hole mass.


2017 ◽  
Vol 768 ◽  
pp. 270-273 ◽  
Author(s):  
Marco Traini ◽  
Matteo Rinaldi ◽  
Sergio Scopetta ◽  
Vicente Vento

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