scholarly journals Multiparticle Production and Initial Quasitemperature from Proton-Induced Carbon Collisions at pLab=31 GeV/c

2020 ◽  
Vol 2020 ◽  
pp. 1-28
Author(s):  
Pei-Pin Yang ◽  
Mai-Ying Duan ◽  
Fu-Hu Liu ◽  
Raghunath Sahoo
Keyword(s):  
Boltzmann Distribution ◽  
Emission Angle ◽  
Target Thickness ◽  
Beam Momentum ◽  
Graphite Target ◽  
Experimental Conditions ◽  
Momentum Spectra ◽  
Charged Pions ◽  
Free Parameters ◽  
Longitudinal Position

The momentum spectra of charged pions (π+ and π−) and kaons (K+ and K−), as well as protons (p), produced in the beam proton-induced collisions in a 90 cm long graphite target (proton-carbon (p-C) collisions) at the beam momentum pLab=31 GeV/c are studied in the framework of a multisource thermal model by using Boltzmann distribution and the Monte Carlo method. The theoretical model results are approximately in agreement with the experimental data measured by the NA61/SHINE Collaboration. The related free parameters (effective temperature, rapidity shifts, and fraction of nonleading protons) and derived quantities (average transverse momentum and initial quasitemperature) under given experimental conditions are obtained. The considered free parameters and derived quantities are shown to be strongly dependent on the emission angle over a range from 0 to 380 mrad and weakly dependent on longitudinal position (graphite target thickness) over a range from 0 to 90 cm.

Collision centrality dependencies of charged pion production in 12C+ 181 Ta collisions at 4.2 A GeV/c

2018 ◽  
Vol 27 (11) ◽  
pp. 1850092 ◽  
Author(s):  
Akhtar Iqbal ◽  
Khusniddin K. Olimov ◽  
Kosim Olimov ◽  
Mushtaq Ahmad ◽  
Sh. Z. Kanokova ◽  
...  
Keyword(s):  
Simple Model ◽  
Pion Production ◽  
Charged Pion ◽  
Heavy Ion ◽  
Emission Angle ◽  
Collision System ◽  
High Energies ◽  
Collision Centrality ◽  
Ion Collisions ◽  
Charged Pions

The collision centrality dependencies of the average kinematical characteristics of the negative and positive pions, produced in [Formula: see text] collisions at [Formula: see text], were investigated. The ratio [Formula: see text] proved to be [Formula: see text], [Formula: see text] and [Formula: see text] in the peripheral, semicentral, and central [Formula: see text] collision events, respectively, decreasing noticeably with increasing collision centrality. The suppression (decrease) of the ratio [Formula: see text] was observed in the semicentral and central [Formula: see text] collisions as compared to the ratio [Formula: see text], estimated using the simple model for [Formula: see text] collision system. The ratio [Formula: see text] estimated using the simple model agreed well with the corresponding ratio [Formula: see text], estimated for [Formula: see text] collisions at [Formula: see text] based on the Wounded Nucleon Model (WNM). Comparison of the emission angle as well as momentum distributions of the charged pions in the peripheral and central [Formula: see text] collisions revealed the significant decrease of the fraction of the relatively fast charged pions (with smaller emission angles) and increase of the fraction of the relatively slow charged pions (with larger emission angles) with an increase in collision centrality. The results of the present analysis can be useful for analysis of the centrality dependence of the charged pion production in heavy ion collisions at high energies.

Combined analysis of midrapidity transverse momentum spectra of the charged pions and kaons, protons and antiprotons in p+p and Pb+Pb collisions at (snn)1/2 = 2.76 and 5.02 TeV at the LHC

2020 ◽  
Vol 35 (29) ◽  
pp. 2050237
Author(s):  
Khusniddin K. Olimov ◽  
Shakhnoza Z. Kanokova ◽  
Alisher K. Olimov ◽  
Kobil I. Umarov ◽  
Boburbek J. Tukhtaev ◽  
...  
Keyword(s):  
Transverse Momentum ◽  
Center Of Mass ◽  
Heavy Ion ◽  
Transverse Flow ◽  
Alice Collaboration ◽  
Momentum Spectra ◽  
Charged Pions ◽  
Transverse Momentum Spectra ◽  
Tsallis Distribution ◽  
Freeze Out

The experimental transverse momentum spectra of the charged pions and kaons, protons and antiprotons, produced at midrapidity in [Formula: see text] collisions at [Formula: see text] and 5.02 TeV, central (0–5%) and peripheral (60–80%) Pb[Formula: see text]+[Formula: see text]Pb collisions at [Formula: see text] TeV, central (0–5%), semicentral (40–50%) and peripheral (80–90%) Pb[Formula: see text]+[Formula: see text]Pb collisions at [Formula: see text] TeV, measured by ALICE collaboration, were analyzed using the Tsallis distribution function as well as Hagedorn formula with the embedded transverse flow. To exclude the influence (on the results) of different available fitting [Formula: see text] ranges in the analyzed collisions, we compare the results obtained from combined (simultaneous) fits of midrapidity spectra of the charged pions and kaons, protons and antiprotons with the above theoretical model functions using the identical fitting [Formula: see text] ranges in [Formula: see text] as well as Pb[Formula: see text]+[Formula: see text]Pb collisions at [Formula: see text] and 5.02 TeV. Using the combined fits with the thermodynamically consistent Tsallis distribution as well as the simple Tsallis distribution without thermodynamical description, it is obtained that the global temperature [Formula: see text] and non-extensivity parameter [Formula: see text] slightly increase (consistently for all the particle types) with an increase in center-of-mass (c.m.) energy [Formula: see text] of [Formula: see text] collisions from 2.76 TeV to 5.02 TeV, indicating that the more violent and faster [Formula: see text] collisions at [Formula: see text] TeV result in a smaller degree of thermalization (higher degree of non-equilibrium) compared to that in [Formula: see text] collisions at [Formula: see text] TeV. The [Formula: see text] values for pions and kaons proved to be very close to each other, whereas [Formula: see text] for protons and antiprotons proved to be significantly lower than that for pions and kaons, that is [Formula: see text]. The results of the combined fits using Hagedorn formula with the embedded transverse flow are consistent with practically no (zero) transverse (radial) flow in [Formula: see text] collisions at [Formula: see text] and 5.02 TeV. Using Hagedorn formula with the embedded transverse flow, it is obtained that the value of the (average) transverse flow velocity increases and the temperature [Formula: see text] decreases with an increase in collision centrality in Pb[Formula: see text]+[Formula: see text]Pb collisions at [Formula: see text] and 5.02 TeV, which is in good agreement with the results of the combined Boltzmann–Gibbs blast-wave fits to the particle spectra in Pb[Formula: see text]+[Formula: see text]Pb collisions at [Formula: see text] and 5.02 TeV in recent works of ALICE collaboration. The temperature [Formula: see text] parameter, which approximates the kinetic freeze-out temperature, was shown to coincide in central (0–5%) Pb[Formula: see text]+[Formula: see text]Pb collisions at [Formula: see text] and 5.02 TeV, which implies, taking into account the results of our previous analysis, that kinetic freeze-out temperature stays practically constant in central heavy-ion collisions in [Formula: see text] GeV energy range.

Analysis of positive pions obtained in d + C collisions at 4.2AGeV/c

2020 ◽  
Vol 29 (06) ◽  
pp. 2050041
Author(s):  
Imran Khan ◽  
Nabeela Feroz ◽  
Ali Zaman ◽  
Naseeb Ullah
Keyword(s):  
Boltzmann Distribution ◽  
High Energy ◽  
Distribution Functions ◽  
Transverse Mass ◽  
Inverse Slope ◽  
Model Calculations ◽  
Momentum Spectra ◽  
Inverse Slope Parameter ◽  
Transverse Momentum Spectra ◽  
High Energy Collisions

Temperature is an important and commonly used parameter among others to study properties of matter created during high energy collisions of nuclei. Experimental data from JINR and UrQMD (version 3.3p2) model simulations have been used to estimate temperature and other properties of positive pions in collisions of deuteron with carbon nuclei at incident momentum of 4.2[Formula: see text]GeV/[Formula: see text] in this paper. Transverse mass and transverse momentum spectra have been used to get inverse slope parameter/temperature of said particles, with the help of some fitting equations. These equations are referred as Hagedorn Thermodynamic and Boltzmann Distribution functions. Such functions or equations are used to describe particles spectra. Temperature of positive pions has been found to be equal to [Formula: see text] and [Formula: see text][Formula: see text]MeV in experimental and model, respectively, using Hagedorn function. Results from both experimental and model calculations have also been compared with each other and thus most reliable fitting function has been suggested. It is found that Hagedorn Thermodynamic function is the most reliable function to get pions’ temperature in said collision system at given momentum. Similarly, results obtained in this paper have been compared with results from other experiments in the world and worthy conclusions have been reached and reported.

Pion PT distribution in hadron–nucleus interaction at accelerator energy

1980 ◽  
Vol 58 (7) ◽  
pp. 969-971 ◽  
Author(s):  
Dipak C. Ghosh
Keyword(s):  
Heavy Nucleus ◽  
Incident Beam ◽  
Beam Momentum ◽  
Nucleus Collision ◽  
Nucleus Interaction ◽  
Charged Pions

In the present work we have investigated the nature of the low PT distribution of secondary charged pions produced in p–nucleus collision in emulsion at the incident beam momentum 22.6 GeV/c. The general characteristics of the PT2 distribution have been found to be the same as in the case of hadron–hadron collisions. A comparison of the PT2 distribution for the two sets of reactions p – heavy nucleus (Nh > 6) and p – light (Nh ≤ 6) is also made.

scholarly journals Momentum Spectra of Charged Pions Produced in Proton-Proton Interactions Between 13 and 28.5 GeV/c

1969 ◽  
Vol 23 (18) ◽  
pp. 1064-1067 ◽  
Author(s):  
Dennis B. Smith ◽  
Robert J. Sprafka ◽  
Jared A. Anderson
Keyword(s):  
Proton Proton ◽  
Momentum Spectra ◽  
Charged Pions

DIFFRACTIVE AND COULOMB DISSOCIATION OF PIONS INTO THREE CHARGED PIONS AT LOW MOMENTUM TRANSFER AT COMPASS

2011 ◽  
Vol 26 (03n04) ◽  
pp. 751-753 ◽  
Author(s):  
◽  
STEFANIE GRABMÜLLER
Keyword(s):  
Momentum Transfer ◽  
Coherent Scattering ◽  
Beam Momentum ◽  
Partial Wave Analysis ◽  
Wave Analysis ◽  
Lead Nucleus ◽  
Coulomb Dissociation ◽  
Photon Exchange ◽  
Charged Pions ◽  
Photo Production

This paper presents an analysis of π- Pb → X- Pb → π-π-π+ Pb events at 190 GeV/c beam momentum and low four-momentum transfer t′ < 0.01 ( GeV /c)2. Coherent scattering off the lead nucleus as a whole dominates with contributions from Reggeon, Pomeron and photon exchange. Photoproduction becomes apparent at lowest t′ and can be extracted statistically as well as by a partial-wave analysis, indicating also the overlap of diffractive and photo-production of the 3π events.

scholarly journals Measurements of $${\Xi \left( 1530\right) ^{0}} $$ and $${\overline{\Xi }\left( 1530\right) ^{0}} $$ production in proton–proton interactions at $$\sqrt{s_{NN}}$$ = 17.3 $$\text{ GeV }$$ in the NA61/SHINE experiment

2021 ◽  
Vol 81 (10) ◽  
Author(s):  
A. Acharya ◽  
H. Adhikary ◽  
K. K. Allison ◽  
N. Amin ◽  
E. V. Andronov ◽  
...  
Keyword(s):  
Phase Space ◽  
Transverse Momentum ◽  
Statistical Model ◽  
Beam Momentum ◽  
Proton Proton ◽  
Model Calculations ◽  
Full Phase Space ◽  
Momentum Spectra ◽  
Transverse Momentum Spectra

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.

scholarly journals Review and Modification of Entropy Modeling for Steric Effects in the Poisson-Boltzmann Equation

Entropy ◽  
2020 ◽  
Vol 22 (6) ◽  
pp. 632
Author(s):  
Tzyy-Leng Horng
Keyword(s):  
Free Energy ◽  
Lattice Gas ◽  
Steric Effect ◽  
Mean Field ◽  
Boltzmann Distribution ◽  
Experimental Conditions ◽  
Ion Concentrations ◽  
Poisson Boltzmann ◽  
Poisson Boltzmann Equation ◽  
Ion Size

The classical Poisson-Boltzmann model can only work when ion concentrations are very dilute, which often does not match the experimental conditions. Researchers have been working on the modification of the model to include the steric effect of ions, which is non-negligible when the ion concentrations are not dilute. Generally the steric effect was modeled to correct the Helmholtz free energy either through its internal energy or entropy, and an overview is given here. The Bikerman model, based on adding solvent entropy to the free energy through the concept of volume exclusion, is a rather popular steric-effect model nowadays. However, ion sizes are treated as identical in the Bikerman model, making an extension of the Bikerman model to include specific ion sizes desirable. Directly replacing the ions of non-specific size by specific ones in the model seems natural and has been accepted by many researchers in this field. However, this straightforward modification does not have a free energy formula to support it. Here modifications of the Bikerman model to include specific ion sizes have been developed iteratively, and such a model is achieved with a guarantee that: (1) it can approach Boltzmann distribution at diluteness; (2) it can reach saturation limit as the reciprocal of specific ion size under extreme electrostatic conditions; (3) its entropy can be derived by mean-field lattice gas model.

scholarly journals Experimental studies of generation of ~100 MeV Au-ions from the laser-produced plasma

2009 ◽  
Vol 27 (1) ◽  
pp. 137-147 ◽  
Author(s):  
L. Láska ◽  
J. Krása ◽  
A. Velyhan ◽  
K. Jungwirth ◽  
E. Krouský ◽  
...  
Keyword(s):  
Laser System ◽  
Experimental Studies ◽  
Target Surface ◽  
Laser Frequency ◽  
Target Thickness ◽  
Focus Position ◽  
Experimental Conditions ◽  
Irradiation Detection ◽  
Fast Ions ◽  
Burn Through

AbstractUsing the PALS iodine laser system, Au ions with the charge state up to 58+ and with the kinetic energy as high as ~300 MeV were generated. The production of these ions was tested in dependence on the laser frequency (1ω, 3ω), on the irradiation/detection angles (0°, 30°), on the focus position with regard to the target surface, and on the target thickness (500 µm, 200 µm, 80 µm). A larger amount of the fastest ions was produced with 1ω than with 3ω, the most of the fast ions were recorded in the direction ~10°from the target normal, the optimum focus position is in front of the target and should be set on with a precision of 50 µm. The forward emission is weaker than the backward one for both of the thinner targets (which burn through) at our experimental conditions.

scholarly journals Searching for Minimum in Dependence of Squared Speed-of-Sound on Collision Energy

2016 ◽  
Vol 2016 ◽  
pp. 1-9 ◽  
Author(s):  
Fu-Hu Liu ◽  
Li-Na Gao ◽  
Roy A. Lacey
Keyword(s):  
Speed Of Sound ◽  
Center Of Mass ◽  
Incident Beam ◽  
Gluon Plasma ◽  
Beam Momentum ◽  
Proton Synchrotron ◽  
Super Proton Synchrotron ◽  
Center Of Mass Energy ◽  
Knee Point ◽  
Charged Pions

Experimental results of the rapidity distributions of negatively charged pions produced in proton-proton (p-p) and beryllium-beryllium (Be-Be) collisions at different beam momentums, measured by the NA61/SHINE Collaboration at the super proton synchrotron (SPS), are described by a revised (three-source) Landau hydrodynamic model. The squared speed-of-sound parametercs2is then extracted from the width of rapidity distribution. There is a local minimum (knee point) which indicates a softest point in the equation of state (EoS) appearing at about40A GeV/c(or 8.8 GeV) incs2excitation function (the dependence ofcs2on incident beam momentum (or center-of-mass energy)). This knee point should be related to the searching for the onset of quark deconfinement and the critical point of quark-gluon plasma (QGP) phase transition.

Sign in / Sign up

Export Citation Format

Share Document