Inclusive charged particle cross sections in full phase space from proton proton interactions at ISR energies

1995 ◽  
Vol 69 (1) ◽  
pp. 55-65
Author(s):  
◽  
A. Breakstone ◽  
H. B. Crawley ◽  
A. Firestone ◽  
M. Gorbics ◽  
...  
2020 ◽  
Vol 2020 ◽  
pp. 1-24
Author(s):  
Aayushi Singla ◽  
M. Kaur

In continuation of our earlier work, in which we analysed the charged particle multiplicities in leptonic and hadronic interactions at different center-of-mass energies in full phase space as well as in restricted phase space using the shifted Gompertz distribution, a detailed analysis of the normalized moments and normalized factorial moments is reported here. A two-component model in which a probability distribution function is obtained from the superposition of two shifted Gompertz distributions, as introduced in our earlier work, has also been used for the analysis. This is the first analysis of the moments with the shifted Gompertz distribution. Analysis has also been performed to predict the moments of multiplicity distribution for the e+e− collisions at s=500 GeV at a future collider.


2021 ◽  
Vol 81 (10) ◽  
Author(s):  
A. Acharya ◽  
H. Adhikary ◽  
K. K. Allison ◽  
N. Amin ◽  
E. V. Andronov ◽  
...  

AbstractDouble-differential yields of $${\Xi \left( 1530\right) ^{0}} $$ Ξ 1530 0 and $${\overline{\Xi }\left( 1530\right) ^{0}} $$ Ξ ¯ 1530 0 resonances produced in p+p interactions were measured at a laboratory beam momentum of 158 $$\text{ GeV }\!/\!c$$ GeV / c . This measurement is the first of its kind in p+p interactions below LHC energies. It was performed at the CERN SPS by the NA61/SHINE collaboration. Double-differential distributions in rapidity and transverse momentum were obtained from a sample of $$26\times 10^6$$ 26 × 10 6 inelastic events. The spectra are extrapolated to full phase space resulting in mean multiplicity of $${\Xi \left( 1530\right) ^{0}} $$ Ξ 1530 0 ($$6.73 \pm 0.25\pm 0.67)\times 10^{-4}$$ 6.73 ± 0.25 ± 0.67 ) × 10 - 4 and $${\overline{\Xi }\left( 1530\right) ^{0}} $$ Ξ ¯ 1530 0 ($$2.71 \pm 0.18\pm 0.18)\times 10^{-4}$$ 2.71 ± 0.18 ± 0.18 ) × 10 - 4 . The rapidity and transverse momentum spectra and mean multiplicities were compared to predictions of string-hadronic and statistical model calculations.


2020 ◽  
Vol 2020 (11) ◽  
Author(s):  
Ansgar Denner ◽  
Giovanni Pelliccioli

Abstract We present results of a computation of NLO QCD corrections to the production of an off-shell top-antitop pair in association with an off-shell W+ boson in proton-proton collisions. As the calculation is based on the full matrix elements for the process $$ \mathrm{pp}\to {\mathrm{e}}^{+}{v}_{\mathrm{e}}{\mu}^{-}{\overline{v}}_{\mu }{\tau}^{+}{v}_{\tau}\mathrm{b}\overline{\mathrm{b}} $$ pp → e + v e μ − v ¯ μ τ + v τ b b ¯ , all off-shell, spin-correlation, and interference effects are included. The NLO QCD corrections are about 20% for the integrated cross-section. Using a dynamical scale, the corrections to most distributions are at the same level, while some distributions show much larger K-factors in suppressed regions of phase space. We have performed a second calculation based on a double-pole approximation. While the corresponding results agree with the full calculation within few per cent for integrated cross-sections, the discrepancy can reach 10% and more in regions of phase space that are not dominated by top-antitop production. As a consequence, on-shell calculations should only be trusted to this level of accuracy.


2020 ◽  
Vol 8 (4) ◽  
Author(s):  
Enrico Bothmann ◽  
Timo Janßen ◽  
Max Knobbe ◽  
Tobias Schmale ◽  
Steffen Schumann

We present a novel approach for the integration of scattering cross sections and the generation of partonic event samples in high-energy physics. We propose an importance sampling technique capable of overcoming typical deficiencies of existing approaches by incorporating neural networks. The method guarantees full phase space coverage and the exact reproduction of the desired target distribution, in our case given by the squared transition matrix element. We study the performance of the algorithm for a few representative examples, including top-quark pair production and gluon scattering into three- and four-gluon final states.


2020 ◽  
Vol 56 (9) ◽  
Author(s):  
Gábor Balassa ◽  
György Wolf

Abstract In this work, we extended our statistical model with charmed and bottomed hadrons, and fit the quark creational probabilities for the heavy quarks, using low energy inclusive charmonium and bottomonium data. With the finalized fit for all the relevant types of quarks (up, down, strange, charm, bottom) at the energy range from a few GeV up to a few tens of GeV’s, the model is now considered complete. Some examples are also given for proton–proton, pion–proton, and proton–antiproton collisions with charmonium, bottomonium, and open charm hadrons in the final state.


Author(s):  
S. Acharya ◽  
◽  
D. Adamová ◽  
S. P. Adhya ◽  
A. Adler ◽  
...  

Abstract The production rates and the transverse momentum distribution of strange hadrons at mid-rapidity ($$\left| y\right| < 0.5$$y<0.5) are measured in proton-proton collisions at $$\sqrt{s}$$s = 13 TeV as a function of the charged particle multiplicity, using the ALICE detector at the LHC. The production rates of $$\mathrm{K}^{0}_{S}$$KS0, $$\Lambda $$Λ, $$\Xi $$Ξ, and $$\Omega $$Ω increase with the multiplicity faster than what is reported for inclusive charged particles. The increase is found to be more pronounced for hadrons with a larger strangeness content. Possible auto-correlations between the charged particles and the strange hadrons are evaluated by measuring the event-activity with charged particle multiplicity estimators covering different pseudorapidity regions. When comparing to lower energy results, the yields of strange hadrons are found to depend only on the mid-rapidity charged particle multiplicity. Several features of the data are reproduced qualitatively by general purpose QCD Monte Carlo models that take into account the effect of densely-packed QCD strings in high multiplicity collisions. However, none of the tested models reproduce the data quantitatively. This work corroborates and extends the ALICE findings on strangeness production in proton-proton collisions at 7 TeV.


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