Soft QCD

2018 ◽  
Author(s):  
John Campbell ◽  
Joey Huston ◽  
Frank Krauss
Keyword(s):  
Experimental Data ◽  
Perturbation Theory ◽  
Phenomenological Models ◽  
Cross Sections ◽  
Strong Interaction ◽  
Scattering Amplitude ◽  
Double Parton Scattering ◽  
Fragmentation Functions ◽  
Effective Models ◽  
Parton Scattering

In Chapter 7, we discuss various aspects of the strong interaction containing a strong non-perturbative or low-scale component. We first briefly summarise the treatment of the total and inelastic cross sections through the analyticity of the scattering amplitude, which leads to the language of Regge poles. We introduce multiple parton interactions, with the underlying theoretical ideas for their description mainly driven by experimental data, before remarking on double parton scattering. Hadronisation, i.e. the transition from the parton of perturbation theory to the observable hadrons, is introduced by first using the idea of fragmentation functions and then discussing two popular phenomenological models describing this transition. We conclude this chapter by remarking on some ideas concerning the description of hadron decays through effective models.

HADRON SPIN-FLIP AMPLITUDE AND SLOPE OF DIFFERENTIAL CROSS-SECTIONS

1999 ◽  
Vol 14 (03) ◽  
pp. 223-230 ◽  
Author(s):  
O. V. SELYUGIN
Keyword(s):  
Experimental Data ◽  
Cross Sections ◽  
Differential Cross ◽  
Scattering Amplitude ◽  
Previous Analysis ◽  
Differential Cross Sections ◽  
Spin Flip ◽  
Flip Amplitude

A possibility to obtain restrictions of the magnitude of the elastic spin-flip hadron scattering amplitude from accurately measured experimental data on the differential cross-sections of elastic hadron–hadron scattering is shown. Appropriate estimations confirm the previous analysis of experimental data at [Formula: see text] GeV and a probable contribution of the hadron spin-flip amplitude.

scholarly journals Production of quarkonium pairs in high-energy proton-proton collisions

2019 ◽  
Vol 199 ◽  
pp. 01021 ◽  
Author(s):  
Wolfgang Schäfer
Keyword(s):  
Pair Production ◽  
Cross Sections ◽  
High Energy ◽  
Open Problems ◽  
Proton Proton ◽  
Proton Collisions ◽  
Double Parton Scattering ◽  
Parton Scattering ◽  
To Receive ◽  
Proton Proton Collisions

Recently there has been much interest in the pair production of quarkonia (charmonia, bottomonia). There are two main motivations behind these studies: first, these processes may help to differentiate between different proposed production mechanisms via color-octet and color-singlet QQ̄ -pair production. Second, the production of quarkonium pairs is expected to receive an important contribution from double parton scattering (DPS) processes. There remain a number of open problems, especially with the CMS and ATLAS data. In the kinematics of these experiments, the leading order of $O\left( {\alpha _S^4} \right)$ is clearly not sufficient. The double parton scattering (DPS) contribution was claimed to be large or even dominant in some corners of the phase space, when the rapidity distance Δy between two J/ψ mesons is large. However the effective cross sections σeff found from empirical analyses are about a factor 2.5 smaller than the usually accepted σeff = 15 mb. Here we discuss, which single-parton-scattering mechanisms can mimic the behavior of DPS induced production. Here especially the production of χ-pairs is important.

scholarly journals Systematic study of proton-induced spallation reactions with microscopic and phenomenological models

2019 ◽  
Vol 25 ◽  
pp. 167
Author(s):  
A. Assimakopoulou ◽  
G. A. Souliotis ◽  
N. Nicolis ◽  
M. Veselsky ◽  
A. Bonasera
Keyword(s):  
Experimental Data ◽  
Phenomenological Models ◽  
Cross Section ◽  
Cross Sections ◽  
Fission Cross Section ◽  
Nucleon Nucleon ◽  
Spallation Reactions ◽  
Intranuclear Cascade ◽  
Nucleon Nucleon Interaction ◽  
Dynamical Description

Proton induced spallation reactions on 238U, 208Pb, 181Ta and 197Au targets at high energies were investigated using the microscopic Contrained Molecular Dynamics (CoMD) model and the phenomenological models INC and SMM. We have calculated the total fission cross sections, the ratio fission cross section to residue cross section, the mass yield curves and the excitation energy after the intranuclear cascade using the CoMD model and the INC/SMM phenomenological models. We made a comparison between the models and the experimental data from the liter- ature. Our calculations showed satisfactory agreement with available experimental data and suggest further improvements in the models. Our study with the CoMD code represents the first complete dynamical description of the spallation process with a microscopic code based on an effective nucleon-nucleon interaction.

scholarly journals DPS mechanism for associated $$c\bar{c} b\bar{b}$$ production in AA UPCs

2020 ◽  
Vol 80 (8) ◽  
Author(s):  
Edgar Huayra ◽  
Emmanuel G. de Oliveira ◽  
Roman Pasechnik
Keyword(s):  
Production Process ◽  
Cross Section ◽  
Photon Energy ◽  
Cross Sections ◽  
Effective Cross Section ◽  
Double Parton Scattering ◽  
Quark Pairs ◽  
Numerical Predictions ◽  
Energy Dependent ◽  
Parton Scattering

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.

Multipomeron theory in the Gribov approach

2016 ◽  
Vol 31 (28n29) ◽  
pp. 1645013
Author(s):  
V. A. Abramovsky ◽  
N. V. Abramovskaya ◽  
N. V. Evstigneeva
Keyword(s):  
Experimental Data ◽  
Elastic Scattering ◽  
Imaginary Part ◽  
Cross Sections ◽  
Energy Region ◽  
Scattering Amplitude ◽  
The Real ◽  
Elastic Scattering Amplitude

Pomeron and non vacuum reggeon parameters which reasonably describe total and elastic cross sections are obtained. The ratio of the real and imaginary part of the forward elastic scattering amplitude is calculated with these parameters and it coincides with the experimental data in the whole energy region. The shower enhancement coefficient in the quasi-eikonal approach appears to be less than unity which corresponds to the definite distribution of parton showers in incident hadrons.

scholarly journals Study of Z boson plus jets events using variables sensitive to double-parton scattering in pp collisions at 13 TeV

2021 ◽  
Vol 2021 (10) ◽  
Author(s):  
◽  
A. Tumasyan ◽  
W. Adam ◽  
J. W. Andrejkovic ◽  
T. Bergauer ◽  
...  
Keyword(s):  
Transverse Momentum ◽  
Cross Sections ◽  
Z Boson ◽  
Proton Collision ◽  
Proton Proton ◽  
Double Parton Scattering ◽  
Important Input ◽  
Momentum Imbalance ◽  
Simulation Parameters ◽  
Parton Scattering

Abstract Double-parton scattering is investigated using events with a Z boson and jets. The Z boson is reconstructed using only the dimuon channel. The measurements are performed with proton-proton collision data recorded by the CMS experiment at the LHC at $$ \sqrt{s} $$ s = 13 TeV, corresponding to an integrated luminosity of 35.9 fb−1 collected in the year 2016. Differential cross sections of Z+ ≥1 jet and Z+ ≥2 jets are measured with transverse momentum of the jets above 20 GeV and pseudorapidity |η| < 2.4. Several distributions with sensitivity to double-parton scattering effects are measured as functions of the angle and the transverse momentum imbalance between the Z boson and the jets. The measured distributions are compared with predictions from several event generators with different hadronization models and different parameter settings for multiparton interactions. The measured distributions show a dependence on the hadronization and multiparton interaction simulation parameters, and are important input for future improvements of the simulations.

scholarly journals Heavy quark production in pA collisions: The double parton scattering contribution

2018 ◽  
Vol 33 (25) ◽  
pp. 1850141 ◽  
Author(s):  
E. R. Cazaroto ◽  
V. P. Gonçalves ◽  
F. S. Navarra
Keyword(s):  
Heavy Quark ◽  
Cross Sections ◽  
Lhcb Collaboration ◽  
Heavy Quark Production ◽  
Double Parton Scattering ◽  
High Energies ◽  
Quark Production ◽  
Scattering Contribution ◽  
Saturation Effects ◽  
Parton Scattering

In this paper, we estimate the double parton scattering (DPS) contribution for the heavy quark production in pA collisions at the LHC. The cross-sections for the charm and bottom production are estimated using the dipole approach, taking into account the saturation effects, which are important for high energies and for the scattering with a large nucleus. We compare the DPS contribution with the single parton scattering one and demonstrate that in the case of charm production, both are similar in the kinematical range probed by the LHC. Predictions for the rapidity range analyzed by the LHCb Collaboration are also presented. Our results indicate that the study of the DPS contribution for the heavy quark production in pPb collisions at the LHC is feasible and can be useful to probe the main assumptions of the approach.

scholarly journals THE EFFECTS OF THE SMALL-t PROPERTIES OF HADRONIC SCATTERING AMPLITUDE ON THE DETERMINATION OF ITS REAL PART

2012 ◽  
Vol 27 (20) ◽  
pp. 1250113 ◽  
Author(s):  
O. V. SELYUGIN
Keyword(s):  
Experimental Data ◽  
Elastic Scattering ◽  
Cross Sections ◽  
Differential Cross ◽  
Scattering Amplitude ◽  
Differential Cross Sections ◽  
Small Momentum Transfer ◽  
Proton Elastic Scattering ◽  
Spin Flip ◽  
The Impact

Taking into account the different forms of the Coulomb-hadron interference phase and the possible spin-flip contribution the new analysis of the experimental data of the proton–antiproton elastic scattering at 3.8<pL<6.0 GeV/c and small momentum transfer is carried out. It is shown that the size of the spin-flip amplitude can be determined from the form of the differential cross-sections at small-t, and the deviation of ρ(s, t) obtained from the examined experimental data of the [Formula: see text] scattering from the analysis1, based on the dispersion relations, is conserved in all examined assumptions. The analysis of the proton–proton elastic scattering at 9<pL<70 GeV/c also shows the impact of the examined effects on the form of the differential cross-sections.

Charge transfer in H+–He+(1s) collisions

1984 ◽  
Vol 62 (4) ◽  
pp. 307-311 ◽  
Author(s):  
Shyamal Datta ◽  
C. R. Mandal ◽  
S. C. Mukherjee
Keyword(s):  
Experimental Data ◽  
Charge Transfer ◽  
Cross Sections ◽  
Ground State ◽  
Intermediate State ◽  
Scattering Amplitude ◽  
Theoretical Calculations ◽  
Analytical Form ◽  
State Approximation ◽  
The Continuum

A new straightforward technique for the calculation of cross sections for electron capture by structureless ions into arbitrary n, l, and m states from the ground state of hydrogenic targets has been presented in the framework of the continuum–intermediate state approximation. We reduce the scattering amplitude to a closed analytical form. We apply this method for the nonsymmetric process H+ + He+(1s) → H(1s, 2s, 2p, 3s, 3p, 3d) + He2+ in the laboratory energy range 50–10 000 keV. Our calculated results are compared with experimental data and existing theoretical calculations.

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