Cumulative hadron production in pA collisions in the framework of z-scaling

2015 ◽  
Vol 39 ◽  
pp. 1560110
Author(s):  
Aparin Alexey ◽  
Tokarev Mikhail

Data on cumulative particle production in pA collisions with momentum [Formula: see text] are analyzed in the [Formula: see text]-scaling approach. Scaling function [Formula: see text] is constructed for different types of target nuclei and inclusive particle angle. The function is expressed via respective inclusive cross section and average multiplicity density of charged particles. This regime corresponds to low [Formula: see text] (low transverse momentum [Formula: see text]). Validity of the concept was verified for this data. A-dependence of the scaling function is studied for low-[Formula: see text] region. Self-similarity of hadron production in pA collisions is confirmed over a wide kinematic range.

1991 ◽  
Vol 06 (03) ◽  
pp. 245-257 ◽  
Author(s):  
R. SZWED ◽  
G. WROCHNA ◽  
A.K. WRÓBLEWSKI

Multiplicity distributions for e+e−→ hadrons recently reported by the AMY and DELPHI collaborations are compared with the data obtained at lower energies. It is proven that the new data obey the KNO-G scaling and the scaling function can be described by the lognormal distribution. The dispersions are linear functions of the mean as for the data measured at lower energies and the standardized moments (such as skewness and kurtosis) are independent of the energy. The energy dependence of the average multiplicity is described by <nch>=β sα−1.


1990 ◽  
Vol 05 (23) ◽  
pp. 1851-1869 ◽  
Author(s):  
R. SZWED ◽  
G. WROCHNA ◽  
A. K. WRÓBLEWSKI

It has been observed that the e+e− multiplicity distributions exhibit the following properties: the dispersions are linear functions of the mean and the distributions obey the KNO-G scaling with the scaling function of the lognormal shape. In this paper the scale invariant branching is assumed as a mechanism within which all these properties could be derived. It is shown that the lognormal shape of the scaling function can be obtained within proposed mechanism by using the generalization of the Central Limit Theorem. The dependence of the average multiplicity on energy is also derived within the postulated framework. It is also shown that many other phenomena encountered in nature have the similar statistical properties.


2000 ◽  
Vol 15 (22) ◽  
pp. 3495-3519 ◽  
Author(s):  
M. V. TOKAREV ◽  
T. G. DEDOVICH

Inclusive jet production in [Formula: see text] and pp collisions at high energies in the framework of the concept of z-scaling is studied. The available experimental data on the cross-section of jet production obtained by the UA1, UA2, CDF and D0 Collaborations are used for analysis. The scaling function ψ(z) is expressed via inclusive cross-section Ed3σ/dq3 and jet multiplicity density ρ(s,η). The properties of z-scaling, the energy and angular independence of ψ(z) and the power behavior, ψ(z)~z-α, of jet and dijet production were found. Based on the properties of z-scaling, the dependence of the cross-section of jets produced in [Formula: see text] and pp collisions on transverse momentum q⊥ over the central range is predicted. The obtained results can be of interest for future experiments planned at RHIC, LHC, HERA and Tevatron to search for new phenomena in hadron–hadron, hadron–nucleus and nucleus–nucleus collisions.


2012 ◽  
Vol 27 (21) ◽  
pp. 1250115 ◽  
Author(s):  
M. V. TOKAREV ◽  
T. G. DEDOVICH ◽  
I. ZBOROVSKÝ

Self-similarity of jet production in pp and [Formula: see text] collisions is studied in the framework of z-scaling. Inclusive jet transverse momentum distributions measured by the STAR Collaboration at RHIC, the CDF and D∅ Collaborations at Tevatron and the CMS and ATLAS Collaborations at LHC are analyzed. The experimental spectra are compared with next-to-leading order QCD calculations in pT- and z-presentations. It is shown that self-similar features of jet cross-sections manifested by the z-scaling give strong restriction on the scaling function ψ(z) at high z. New results on energy and angular independence and asymptotic behavior of ψ(z) are discussed. The obtained results are considered as confirmation of self-similarity of jet production, fractality of hadron structure and locality of constituent interactions at small scales.


2021 ◽  
Vol 2021 (2) ◽  
Author(s):  
M. Boglione ◽  
A. Simonelli

Abstract Factorizing the cross section for single hadron production in e+e− annihilations is a highly non trivial task when the transverse momentum of the outgoing hadron with respect to the thrust axis is taken into account. We work in a scheme that allows to factorize the e+e−→ H X cross section as a convolution of a calculable hard coefficient and a Transverse Momentum Dependent (TMD) fragmentation function. The result, differential in zh, PT and thrust, will be given to all orders in perturbation theory and explicitly computed to Next to Leading Order (NLO) and Next to Leading Log (NLL) accuracy. The predictions obtained from our computation, applying the simplest and most natural ansatz to model the non-perturbative part of the TMD, are in exceptional agreement with the experimental measurements of the BELLE Collaboration. The factorization scheme we propose relates the TMD parton densities defined in 1-hadron and 2-hadron processes, restoring the possi- bility to perform global phenomenological studies of TMD physics including experimental data from semi-inclusive deep inelastic scattering, Drell-Yan processes, e+e−→ H1H2X and e+e−→ H X annihilations.


2020 ◽  
Vol 2020 (9) ◽  
Author(s):  
Patrick Draper ◽  
Jonathan Kozaczuk ◽  
Scott Thomas

Abstract A primary goal of a future e+e− collider program will be the precision measurement of Higgs boson properties. For practical reasons it is of interest to determine the minimal set of detector specifications required to reach this and other scientific goals. Here we investigate the precision obtainable for the e+e−Zhμ+μ−X inclusive cross section and the Higgs boson mass using the di-muon recoil method, considering a detector that has only an inner tracking system within a solenoidal magnetic field, surrounded by many nuclear interaction lengths of absorbing material, and an outer muon identification system. We find that the sensitivity achievable in these measurements with such a tracking detector is only marginally reduced compared to that expected for a general purpose detector with additional electromagnetic and hadronic calorimeter systems. The difference results mainly from multi-photon backgrounds that are not as easily rejected with tracking detectors. We also comment on the prospects for an analogous measurement of the e+e−→Zh→e+e−X inclusive cross section. Finally, we study searches for light scalars utilizing the di-muon recoil method, estimating the projected reach with a tracking or general purpose detector.


2003 ◽  
Vol 18 (08) ◽  
pp. 1185-1192
Author(s):  
◽  
STEFAN BERNREUTHER

The HERMES experiment has measured double spin asymmetries in the cross section for deep–inelastic scattering of longitudinally polarized positrons on longitudinally polarized 3 He (1995), 1 H (1996/97), and 2 D (1998) targets. A kinematic range of 0.023 < x < 0.6, and 1 GeV 2 < Q2 < 15 GeV 2 has been covered. From these asymmetries, based on inclusive and semi–inclusive measurements, polarized quark distributions are extracted as a function of x for up [Formula: see text] and down [Formula: see text] flavors as well as for valence and sea quarks. In the measured range, the up quark polarization is positive while the down quark polarization is negative. The sea quark polarization is compatible with zero. In this analysis all sea quark polarizations have been assumed to be flavor symmetric. Presently HERMES is analyzing a high statistics 2 D data sample taken in 1999-2000. For these data it is possible to identify pions and kaons with a RICH detector which was installed in 1998. This will enable an extraction of the individual sea quark flavors [Formula: see text], [Formula: see text], and [Formula: see text] without any symmetry assumptions.


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