Kinetic Temperature Research Articles

Active Brownian motion of emulsion droplets driven by nanoscale effects under laser irradiation

This work presented the results of an experimental study of dynamics of emulsion complex composition droplets under laser irradiation. The oil-in-water emulsion consisted of liquid paraffin droplets containing magnetite nanoparticles and was placed in an aqueous solution of the surfactant. The magnetite nanoparticles had characteristic dimensions of 10−8 m, which correspond to the dimensions of molecular motors in living cells. For all emulsion droplets, motion in transitional and normal diffusive modes was observed. The effective kinetic temperature of emulsion droplets was 3.5 × 103 eV and was exceeded the temperature of thermal motion of the medium molecules, 0.03 eV. Experimentally observed active Brownian motion of emulsion droplets was a result of intra-droplet motion of magnetite nanoparticles absorbing laser irradiation. Laser irradiation caused the magnetite nanoparticle heating, which generated a thermophoretic force. As a result of viscous friction forces, the nanoparticles transferred momentum to the emulsion droplet, causing its motion.

NH3 (1,1) hyperfine intensity anomalies in infall sources

Identifying infall motions is crucial for our understanding of accretion processes in regions of star formation. The NH3 (1,1) hyperfine intensity anomaly (HIA) has been proposed to be a readily usable tracer for such infall motions in star-forming regions harboring young stellar objects at very early evolutionary stages. In this paper, we seek to study the HIA toward 15 infall candidate regions in order to assess its reliability as an infall tracer. Using deep observations of the NH3 (1, 1) transition with the Effelsberg 100 m telescope, we identified HIAs toward all 15 targets. Of the 15 sources, 14 exhibit anomalous intensities in either the inner or outer satellite lines. All the derived HIAs conform to the framework of the existing two models, namely hyperfine selective trapping (HST) and systematic contraction or expansion motion (CE) models. In our sample of infall candidates, the majority of the HIAs remain consistent with the HST model. Only in three targets are the HIAs consistent with infall motions under the CE model. Thus, the HIA could indeed be used as an infall tracer, but does not appear to be highly sensitive to infall motions in our single-dish data. Nevertheless, the emission could be blended with emission from outflow activities. HIAs consistent with the HST model show stronger anomalies with increasing kinetic temperatures (TK), which is expected based on the HST model. On the other hand, HIAs consistent with infall motions show little dependence on Tk . Therefore, HIAs may preferably trace the infall of cold gas.

Toward a robust physical and chemical characterization of heterogeneous lines of sight: The case of the Horsehead nebula

Dense and cold molecular cores and filaments are surrounded by an envelope of translucent gas. Some of the low- J emission lines of and isotopologues are more sensitive to the conditions either in the translucent environment or in the dense and cold one because their intensities result from a complex interplay of radiative transfer and chemical properties of these heterogeneous lines of sight (LoSs). We extend our previous single-zone modeling with a more realistic approach that introduces multiple layers to take account of possibly varying conditions along the LoS. We used the IRAM-30m data from the ORION-B large program toward the Horsehead nebula in order to demonstrate our method's capability and effectiveness. We propose a cloud model composed of three homogeneous slabs of gas along each LoS, representing an outer envelope and a more shielded inner layer. We used the non-LTE radiative transfer code RADEX to model the line profiles from the kinetic temperature ( the volume density ( kinematics, and chemical properties of the different layers. We then used a fast and robust maximum likelihood estimator to simultaneously fit the observed lines of the and isotopologues. To limit the variance on the estimates, we propose a simple chemical model by constraining the column densities. A single-layer model cannot reproduce the spectral line asymmetries that result from a combination of different radial velocities and absorption effects among layers. A minimal heterogeneous model (three layers only) is sufficient for the Horsehead application, as it provides good fits of the seven fitted lines over a large part of the studied field of view. The decomposition of the intensity into three layers allowed us to discuss the distribution of the estimated physical or chemical properties along the LoS. About 80<!PCT!> of the integrated intensity comes from the outer envelope, while $ of the integrated intensity of the and lines of comes from the inner layer. For the lines of the and the isotopologues, integrated intensities are more equally distributed over the cloud layers. The estimated column density ratio NCeiO in the envelope increases with decreasing visual extinction, and it reaches $25$ in the pillar outskirts. While the inferred of the envelope varies from $25$ to K$ that of the inner layer drops to K$ in the western dense core. The estimated in the inner layer is pccm$ toward the filament, and it increases by a factor of ten toward dense cores. Our proposed method correctly retrieves the physical and chemical properties of the Horsehead nebula. It also offers promising prospects for less supervised model fits of wider-field datasets.

Analysis of transverse momentum spectra of protons, deuterons, and tritons in symmetric heavy-ion collisions at √(s_NN ) = 200 GeV at the RHIC

Abstract The blast wave model with Tsallis statistics is used to analyze the transverse momentum spectra of the protons (p), deuteron (d), and triton (t) in √(s_NN ) = 200 GeV gold-gold (Au-Au) collisions at RHIC in various centrality bins. In particular transverse momentum ranges, model results closely match experimental data from the PHENIX (p) and STAR (d and t) Collaborations. The data is compared with protons obtained in Cu+Cu collisions and deuteron and triton in Ru+Ru collisions at 200 GeV, center of mass energy from STAR collaboration. Particle spectra are used to derive the kinetic freeze-out temperatures, transverse flow velocities, and freeze-out volumes. According to the findings, the kinetic freeze-out temperature rises as one goes from the central to peripheral collisions. In this transition, the transverse flow velocity and the freeze-out volume both drop. In the collisions of both Collaborations, this work reveals mass-dependent kinetic freeze-out temperature and differential volume possibilities. On the whole, the non-extensivity parameter q decreases with increasing centrality of the studied heavy-ion collisions, and heavier mass particles have smaller values of q, which implies higher degrees of thermalization and equilibrium in more central collisions and for heavier particles.

Massive Star Formation Starts in Subvirial Dense Clumps Unless Resisted by Strong Magnetic Fields

Knowledge of the initial conditions of high-mass star formation is critical for theoretical models, but are not well observed. Built on our previous characterization of a Galaxy-wide sample of 463 candidate high-mass starless clumps (HMSCs), here we investigate the dynamical state of a representative subsample of 44 HMSCs (radii 0.13–1.12 pc) using Green Bank Telescope NH3 (1,1) and (2,2) data from the Radio Ammonia Mid-Plane Survey pilot data release. By fitting the two NH3 lines simultaneously, we obtain velocity dispersion, gas kinetic temperature, NH3 column density and abundance, Mach number, and virial parameter. Thermodynamic analysis reveals that most HMSCs have Mach number <5, inconsistent with what have been considered in theoretical models. All but one (43 out of 44) of the HMSCs are gravitationally bound with virial parameter α vir < 2. Either these massive clumps are collapsing or magnetic field strengths of 0.10–2.65 mG (average 0.51 mG) would be needed to prevent them from collapsing. The estimated B-field strength correlates tightly with density, Best/mG=0.269(nH2/104cm−3)0.61 , with a similar power-law index as found in observations but a factor of 4.6 higher in strength. For the first time, the initial dynamical state of high-mass formation regions has been statistically constrained to be subvirial, in contradiction to theoretical models in virial equilibrium and in agreement with the lack of observed massive starless cores. The findings urge future observations to quantify the magnetic field support in the prestellar stage of massive clumps, which has rarely been explored so far, toward a full understanding of the physical conditions that initiate massive star formation.

Harmonic chain driven by active Rubin bath: transport properties and steady-state correlations

Characterizing the properties of an extended system driven by active reservoirs is a question of increasing importance. Here, we address this question in two steps. We start by investigating the dynamics of a probe particle connected to an ‘active Rubin bath’: a linear chain of overdamped run-and-tumble particles. We derive exact analytical expressions for the effective noise and dissipation kernels, acting on the probe and show that the active nature of the bath leads to a modified fluctuation–dissipation relation. In the next step, we study the properties of an activity-driven system, modelled by a chain of harmonic oscillators connected to two such active reservoirs at the two ends. We show that the system reaches a non-equilibrium stationary state (NESS), remarkably different from that generated due to a thermal gradient. We characterize this NESS by computing the kinetic temperature profile, spatial and temporal velocity correlations of the oscillators, and the average energy current flowing through the system. It turns out that the activity drive leads to the emergence of two characteristic length-scales, proportional to the activities of the reservoirs. Strong signatures of activity are also manifest in the anomalous short-time decay of the velocity autocorrelations. Finally, we find that the energy current shows a non-monotonic dependence on the activity drive and reversal in direction, corroborating previous findings.

A thermodynamic model of inflation without inflaton field

In the framework of geometrothermodynamics, we explore how to construct an inflationary cosmic fluid without requiring inflaton fields. To do so, we employ standard radiation and matter as barotropic background, speculating on the existence of a further real fluid, interpreted as a possible matter with pressure constituent. We thus illustrate its main characteristics, showing how it may face the flatness and horizon problems, yielding an equivalent number of e-foldings, compatible with theoretical expectations. Moreover, we calculate the associated equilibrium and kinetic temperatures, and compute out-of-equilibrium properties, in terms of particle production and effective reheating mechanism. Accordingly, we revise how inflation ends and how to fix the free parameters of our model from observations. Last but not least, we propose how to obtain a bare cosmological constant that could relate the late-time acceleration to inflation, aiming to unify the two approaches. Finally, we discuss the corresponding theoretical implications of our treatment in contrast to the standard approach reliant on scalar field potentials, emphasizing the main advantages and disadvantages.

On the kinetic temperature of a one-dimensional crystal on the long-time scale

We investigate the dynamics of the kinetic temperature of a finite one-dimensional harmonic chain, the evolution of which is initiated by a thermal shock. We demonstrate that the kinetic temperature returns arbitrarily close to its initial state (the one immediately following the thermal shock) infinitely many times, and we give an estimate for the time elapsed until the recurrence. This assertion is closely related to the Poincare recurrence theorem and we discuss their relation. To estimate the recurrence time we use its averaging along system’s trajectory and provide a rigorous mathematical definition of the mean recurrence time. It turns out that the mean recurrence time exponentially increases with the number of particles in the chain. A connection is established between this problem and the local theorems of large deviations theory.Previous studies have shown that in such a one-dimensional harmonic chain, at times of order N, a thermal echo phenomenon is observed — a sharp increase in the amplitude of kinetic temperature fluctuations. In the present work, we give a rigorous mathematical formulation to this phenomenon and estimate the amplitude of the fluctuations.The research is funded by the Ministry of Science and Higher Education of the Russian Federation within the framework of the Research Center of World-Class Program: Advanced Digital Technologies (agreement №075-15-2020-311 dated 04.20.2022).

Response of Upper Ocean to Parameterized Schemes of Wave Breaking under Typhoon Condition

The study of upper ocean mixing processes, including their dynamics and thermodynamics, has been a primary focus for oceanographers and meteorologists. Wave breaking in deep water is believed to play a significant role in these processes, affecting air–sea interactions and contributing to the energy dissipation of surface waves. This, in turn, enhances the transfer of gas, heat, and mass at the ocean surface. In this paper, we use the FVCOM-SWAVE coupled wave and current model, which is based on the MY-2.5 turbulent closure model, to examine the response of upper ocean turbulent kinetic energy (TKE) and temperature to various wave breaking parametric schemes. We propose a new parametric scheme for wave breaking energy at the sea surface, which is based on the correlation between breaking wave parameter RB and whitecap coverage. The impact of this new wave breaking parametric scheme on the upper ocean under typhoon conditions is analyzed by comparing it with the original parametric scheme that is primarily influenced by wave age. The wave field simulated by SWAVE was verified using Jason-3 satellite altimeter data, confirming the effectiveness of the simulation. The simulation results for upper ocean temperature were also validated using OISST data and Argo float observational data. Our findings indicate that, under the influence of Typhoon Nanmadol, both parametric schemes can transfer the energy of sea surface wave breaking into the seawater. The new wave breaking parameter RB scheme effectively enhances turbulent mixing at the ocean surface, leading to a decrease in sea surface temperature (SST) and an increase in mixed layer depth (MLD). This further improves upon the issue of uneven mixing of seawater at the air–sea interface in the MY-2.5 turbulent closure model. However, it is important to note that wave breaking under typhoon conditions is only one aspect of wave impact on ocean disturbances. Therefore, further research is needed to fully understand the impact of waves on upper ocean mixing, including the consideration of other wave mechanisms.

The factors that influence protostellar multiplicity

Context. Protostellar multiplicity is common at all stages and mass ranges. However, the factors that determine the multiplicity of protostellar systems have not been systematically characterized through their molecular gas. Aims. We characterize the physical properties of the Perseus molecular cloud at ≥5000 AU scales by mapping the diagnostic molecular lines. Methods. We used Nobeyama 45m Radio Observatory (NRO) on-the-fly maps of HCN, HNC, HCO+, and N2H+ (J=1–0) toward five subregions in Perseus, complemented with single-pointing Atacama Pathfinder Experiment (APEX) observations of HNC (J = 4–3), to derive the physical parameters of the dense gas. The spatial resolutions of both observations were ~18″, which is equivalent to ~5000 AU scales at the distance of Perseus. The kinetic gas temperature was derived from the I(HCN)/I(HNC) J ratio, and the H2 density was obtained from the HNC J=4–3/J=1–0 ratio. These parameters were used to obtain the N2H+ (cold) and HCO+ (warm) gas masses. The inferred and derived parameters were then compared to source the parameters, including protostellar multiplicity, bolometric luminosity, and dust envelope mass. Results. The inferred mean kinetic gas temperature (I(HCN)/I(HNC) J=1–0 ratio; ranging between 15 and 26 K), and H2 volumetric density (HNC J=4–3/J=1–0; 105−106 cm−3) are not correlated with multiplicity in Perseus. The derived gas and dust masses, 1.3 to 16 × 10−9 M⊙ for the cold-gas mass (N2H+), 0.1 to 25 M⊙ for the envelope dust masses (850 μm), and 0.8 to 10 × 10−10 M⊙ for the warm-gas mass (HCO+), are correlated to multiplicity and to the number of protostellar components. The warm-gas masses are lower by a factor of 16 than the cold-gas masses. Conclusions. The gas and dust mass is correlated to multiplicity at ~5000 AU scales in Perseus. Higher-order multiples tend to have higher gas and dust masses in general, while close binaries (separations ≤7″) and single protostars have similar gas and dust mass distributions. On the other hand, the H2 density and kinetic gas temperature are not correlated with multiplicity.

Molecular gas excitation in the circumgalactic medium of MACS1931–26

The evolution of galaxies is largely affected by exchanging material with their close environment, the circumgalactic medium (CGM). In this work, we investigate the CGM and the interstellar medium (ISM) of the bright central galaxy (BCG) of the galaxy cluster, MACS1931−26 at z ∼ 0.35. We detected [CI](2−1), 12CO(1−0), and 12CO(7−6) emission lines with the APEX 12-m and NRO 45-m telescopes. We complemented these single-dish observations with 12CO(1−0), 12CO(3−2), and 12CO(4−3) ALMA interferometric data and inferred the cold molecular hydrogen physical properties. Using a modified large velocity gradient (LVG) model, we modelled the CO and CI emission of the CGM and BCG to extract the gas thermodynamical properties, including the kinetic temperature, the density, and the virialisation factor. Our study shows that the gas in the BCG is highly excited, comparable to the gas in local ultra luminous infrared galaxies (ULIRGs), while the CGM is likely less excited, colder, less dense, and less bound compared to the ISM of the BCG. The molecular hydrogen mass of the whole system derived using [CI](2−1) is larger than the mass derived from 12CO(1−0) in literature, showing that part of the gas in this system is CO-poor. Additional spatially resolved CI observations in both transitions, [CI](1−0) and [CI](2−1), and the completion of the CO SLED with higher CO transitions are crucial to trace the different phases of the gas in such systems and constrain their properties.

Extended CO(1–0) survey and ammonia measurements towards two bubble regions in W5

The feedback effect of massive stars can either accelerate or inhibit star formation activity within molecular clouds. Studying the morphology of molecular clouds near W5 offers an excellent opportunity to examine this feedback effect. We conducted a comprehensive survey of the W5 complex using the Purple Mountain Observatory 13.7 m millimeter telescope. This survey includes 12CO, 13CO, and C18O (J = 1 − 0), with a sky coverage of 6.6 deg2 (136.0° &lt; l &lt; 138.75°, 0° &lt; b &lt; 2.4°). Furthermore, we performed simultaneous observations of the NH3 (1,1) and NH3 (2,2) lines in the four densest star-forming regions of W5, using the 26 m radio telescope of the Xinjiang Astronomy Observatory (XAO). Our analysis of the morphological distribution of the molecular clouds, distribution of high-mass young stellar objects (HMYSOs), 13CO/C18O abundance ratio, and the stacked average spectral line distribution at different 8 μm thresholds provide compelling evidence of triggering. Within the mapped region, we identified a total of 212 molecular clumps in the 13CO cube data using the astrodendro algorithm. Remarkably, approximately 26.4% (56) of these clumps demonstrate the potential to form massive stars and 42.9% (91) of them are gravitationally bound. Within clumps that are capable of forming high-mass stars, there is a distribution of class I YSOs, all located in dense regions near the boundaries of the HII regions. The detection of NH3 near the most prominent cores reveals moderate kinetic temperatures and densities (as CO). Comparing the Tkin and Tex values reveals a reversal in trends for AFGL 4029 (higher Tex and lower Tkin) and W5-W1, indicating the inadequacy of optically thick CO for dense region parameter calculations. Moreover, a comparison of the intensity distributions between NH3 (1,1) and C18O (1–0) in the four densest region reveals a notable depletion effect in AFGL 4029, characterised by a low Tkin (9 K) value and a relatively high NH3 column density, 2.5 × 1014 cm−2. By classifying the 13CO clumps as: “feedback,” “non-feedback,” “outflow,” or “non-outflow” clumps, we observe that the parameters of the “feedback” and “outflow” clumps exhibit variations based on the intensity of the internal 8 μm flux and the outflow energy, respectively. These changes demonstrate a clear linear correlation, which distinctly separate them from the parameter distributions of the “non-feedback” and “non-outflow” clumps, thus providing robust evidence to support a triggering scenario.

Molecular Oxygen Abundance in Galactic Massive Star Formation Regions Based on SWAS Observations

Molecular oxygen abundance is a key parameter in understanding the chemical network of the interstellar medium. We estimate the molecular oxygen column density and abundance for a sample of Galactic massive star formation regions based on observations from the Submillimiter Wave Astronomy Satellite (SWAS) survey. We obtained an averaged O2 spectrum based on this sample using the (SWAS) survey data (O2, 487.249 GHz, N = 3–1, J = 3–2). No emission or absorption feature is seen around the supposed central velocity with a total integration time of t total = 8.67 × 103 hr and an rms noise per channel of 1.45 mK. Assuming a kinetic temperature T kin = 30 K, we derive the 3σ upper limit of the O2 column density to be 3.3 × 1015 cm−2, close to the lowest values reported in Galactic massive star formation regions in previous studies. The corresponding O2 abundance upper limit is 6.7 × 10−8, lower than all previous results based on SWAS observations and is close to the lowest reported value in massive star formation regions. On a galactic scale, our statistical results confirm a generally low O2 abundance for Galactic massive star formation regions. This abundance is also lower than results reported in extragalactic sources.

Heteroleptic Complexes of Ruthenium Nitrosyl with Pyridine and Bypiridine-Synthesis and Photoisomerization.

The reaction of [RuNO(Py)2Cl2OH] with bipyridine in water-ethanol media results in trans-(NO, OH)-[RuNO(Py)(Bpy)ClOH]+ with an acceptable yield (60-70%) as hexafluorophosphate salt. Further treatment of the hydroxy-complex with concentrated HF quantitatively leads to trans-(NO, F)-[RuNO(Py)(Bpy)ClF]+. Despite the chirality of both coordination spheres, the hexafluorophosphate salts crystallized as racemates. A NO-linkage isomerism study of the obtained complexes was performed at 80 K with different excitation wavelengths (405, 450, 488 nm). The most favorable wavelengths for the MS1 isomer (Ru-ON) formation were 405 and 450 nm, where the linkage isomer populations were 17% and 1% for [RuNO(Py)(Bpy)ClOH]PF6 and [RuNO(Py)(Bpy)ClF]PF6. The shift of the excitation wavelength to the green (488 nm) sharply decreased the MS1 population. The IR-spectral signatures of MS1 were registered. Reverse-transformation Ru-ON (MS1)-Ru-NO (GS) was investigated for [RuNO(Py)(Bpy)ClOH]PF6 using IR and DSC techniques that made it possible to determine the kinetic parameters (Ea and k0) and decay temperature.

Dissociative recombination of rotationally cold ArH+

We have experimentally studied dissociative recombination (DR) of electronically and vibrationally relaxed ArH+ in its lowest rotational levels, using an electron-ion merged-beams setup at the Cryogenic Storage Ring. We report measurements for the merged-beams rate coefficient of ArH+ and compare it to published experimental and theoretical results. In addition, by measuring the kinetic energy released to the DR fragments, we have determined the internal state of the DR products after dissociation. At low collision energies, we find that the atomic products are in their respective ground states, which are only accessible via nonadiabatic couplings to neutral Rydberg states. Published theoretical results for ArH+ have not included this DR pathway. From our measurements, we have also derived a kinetic temperature rate coefficient for use in astrochemical models. Published by the American Physical Society 2024

A physics-guided automated machine learning approach for obtaining surface radiometric temperatures on sunny days based on UAV-derived images

Urban surface radiometric temperatures, approximate to the surface kinetic temperatures, are predominantly retrieved using satellites or unmanned aerial vehicles (UAVs) and exhibit pronounced spatiotemporal variations. Despite numerous methods ranging from empirical to physical models for obtaining urban microscale surface radiometric temperatures via UAVs, challenges remain given the limited physical significance and substantial professional barriers to method application. Against this background, this study introduces a novel and straightforward approach for acquiring spatially distributed radiometric temperatures on sunny days without understanding the complex radiative transfer process as well as acquiring low-altitude atmospheric parameters. An automated machine learning was employed to train a model capable of efficiently estimating radiometric temperatures. Training and testing datasets were created based on the urban radiative transfer equation, incorporating three independent variables: UAV-measured surface brightness temperature, broadband emissivity, and sky view factor, which collectively represent the diverse thermal environments across different surface characteristics and urban layouts during sunny transitional and summer seasons. The model's accuracy was subsequently confirmed through direct comparisons with radiometric temperatures retrieved from UAV-collected multimodal images and kinetic temperatures synchronously collected on the ground across four periods. The results indicate that AutoGluon achieved high accuracy (MAE: 0.04 K; RMSE: 0.06 K; R2: 0.99). Additional ground measurement validations further demonstrated the model's reliability, with absolute biases on sunlit surfaces maintained within 1.25 K. Given its capability for real-time, high-spatial-resolution mapping of radiometric temperatures (April test: 8.70 cm, July test: 6.89 cm) in urban microscales with considerable heterogeneity, such a method is envisioned to be an effective tool for the dynamic monitoring and management of thermal environments at the microscale level in urban settings.

Interplay of Kinetic and Thermodynamic Factors in the Stationary Composition of Vapor-Liquid-Solid IIIVxV1-x Nanowires.

Compositional control over vapor-liquid-solid III-V ternary nanowires based on group V intermix (VLS IIIVxV1-x NWs) is complicated by the presence of a catalyst droplet with extremely low and hence undetectable concentrations of group V atoms. The liquid-solid and vapor-solid distributions of IIIVxV1-x NWs at a given temperature are influenced by the kinetic parameters (supersaturation and diffusion coefficients in liquid, V/III flux ratio in vapor), temperature and thermodynamic constants. We analyze the interplay of the kinetic and thermodynamic factors influencing the compositions of VLS IIIVxV1-x NWs and derive a new vapor-solid distribution that contains only one parameter of liquid, the ratio of the diffusion coefficients of dissimilar group V atoms. The unknown concentrations of group V atoms in liquid have no influence on the NW composition at high enough levels of supersaturation in liquid. The simple analytic shape of this vapor-solid distribution is regulated by the total V/III flux ratio in vapor. Calculating the temperature-dependent desorption rates, we show that the purely kinetic regime of the liquid-solid growth occurs for VLS IIIVxV1-x NWs in a wide range of conditions. The model fits the data well on the vapor-solid distributions of VLS InPxAs1-x and GaPxAs1-x NWs and can be used for understanding and controlling the compositions of any VLS IIIVxV1-x NWs, as well as modeling the compositional profiles across NW heterostructures in different material systems.

Bulk properties of the system in Au–Au collisions at 3 GeV and their dependence on collision centrality and particle rapidity

We analyze the transverse momentum spectra of proton (p), deuteron (d), triton (t), and helium (3He and 4He) in different centrality intervals in various rapidity slices in gold–gold (Au–Au) collisions at sNN=3 GeV. We apply the blast-wave model with Tsallis statistics (TBW) to transverse momentum spectra of the particles, which fits well the data of STAR Collaboration. The freezeout parameters such as kinetic freezeout temperature, transverse flow velocity, and kinetic freezeout volume are extracted. Our findings reveal that central collisions exhibit higher values for the kinetic freezeout temperature, transverse flow velocity, and kinetic freezeout volume (which means that the central collisions are more hot and expansive), and observed that they decrease from central to peripheral collisions, and the former two parameters decrease from backward rapidity regions to mid-rapidity. This indicates a rapid expansion of the system in central collisions and in backward rapidities. The above parameters are mass-dependent, and the former increases, while the latter two decrease for heavier particles, reflecting the multiple kinetic freezeout and volume differential freezeout scenarios. Besides, the entropy parameter (q) is extracted, and it increases from peripheral to central and from backward to mid-rapidity regions.

Dependence of thermodynamic quantities at freeze-out on pseudorapidity and collision energy in p-p collisions at LHC energies* *Supported by Princess Nourah bint Abdulrahman University Researchers Supporting Project number (PNURSP2024R106), Princess Nourah bint Abdulrahman University, Riyadh, Saudi Arabia. In addition, the authors extend their appreciation to the Deanship of Scientific Research at Northern Border University, Arar, KSA for funding this research

The transverse momentum distributions of charged hadrons produced in proton-proton collisions at center-of-mass energies ( ) of 0.9 TeV and 2.36 TeV, as measured by the CMS detector at the Large Hadron Collider (LHC), have been analyzed within various pseudorapidity classes utilizing the thermodynamically consistent Tsallis distribution. The fitting procedure resulted in the key parameters, namely, effective temperature (T), non-extensivity parameter (q), and kinetic freezeout volume (V). Additionally, the mean transverse momentum ( ) and initial temperature (Ti ) of the particle source are determined through the fit function and string percolation method, respectively. An alternative method is employed to calculate the kinetic freezeout temperature ( ) and transverse flow velocity ( ) from T. Furthermore, thermodynamic quantities at the freezeout, including energy density (ε), particle density (n), entropy density (s), pressure (P), and squared speed of sound ( ), are computed using the extracted T and q. It is also observed that, with a decrease in pseudorapidity, all thermodynamic quantities except V and q increase. This trend is attributed to greater energy transfer along the mid pseudorapidity. q increases towards higher values of pseudorapidity, indicating that particles close to the beam axis are far from equilibrium. Meanwhile, V remains nearly independent of pseudorapidity. The excitation function of these parameters (q) shows a direct (inverse) correlation with collision energy. The ε, n, s, and P show a strong dependence on collision energies at low pseudorapidities. Explicit verification of the thermodynamic inequality suggests the formation of a highly dense droplet-like Quark-Gluon Plasma (QGP). Additionally, the inequality is explicitly confirmed, aligning with the evolution of the produced fireball.

Estimation of kinetic temperature and radial flow velocity using identified hadrons and light (anti-)nuclei produced in relativistic heavy-ion collisions at energies available at BNL RHIC and CERN LHC

Estimation of kinetic temperature and radial flow velocity using identified hadrons and light (anti-)nuclei produced in relativistic heavy-ion collisions at energies available at BNL RHIC and CERN LHC