Thermal freeze-out and collective signatures in $$pp$$ collisions with a non-extensive statistical study on energy and pseudorapidity systematics
Abstract This paper presents a comprehensive analysis of the double-differential $$p_T$$ distributions of charged particles across twelve pseudorapidity regions ( $$|\eta | < 2.4$$ , bin width $$\Delta \eta = 0.2$$ ) in $$pp$$ collisions at $$\sqrt{s} = 0.9$$ , 2.36, and 7 TeV. Using a modified T...
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| Main Authors: | , , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Nature Portfolio
2025-07-01
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| Series: | Scientific Reports |
| Online Access: | https://doi.org/10.1038/s41598-025-08380-w |
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| Summary: | Abstract This paper presents a comprehensive analysis of the double-differential $$p_T$$ distributions of charged particles across twelve pseudorapidity regions ( $$|\eta | < 2.4$$ , bin width $$\Delta \eta = 0.2$$ ) in $$pp$$ collisions at $$\sqrt{s} = 0.9$$ , 2.36, and 7 TeV. Using a modified Tsallis function incorporating an effective transverse flow velocity, we achieve excellent agreement between the model and experimental data, with consistent fit quality across all $$p_T$$ ranges (validated by Data/Fit panels). The extracted parameters including kinetic freeze-out temperature ( $$T_0$$ ), mean transverse flow velocity ( $$\langle \beta _T\rangle$$ ), non-extensivity parameter ( $$q$$ ), and mean transverse momentum ( $$\langle p_T \rangle$$ ) reveal systematic dependencies on $$\eta$$ and $$\sqrt{s}$$ . Both $$T_0$$ , $$\langle \beta _T\rangle$$ , and $$\langle p_T \rangle$$ decrease with $$|\eta |$$ , attributed to reduced energy deposition and weaker thermalization in fragmentation-dominated high- $$|\eta |$$ regions. These parameters also exhibit marked growth with $$\sqrt{s}$$ , reflecting collision-energy-driven dynamics. In contrast, $$q$$ increases with $$|\eta |$$ , signaling greater deviation from thermal equilibrium (Boltzmann limit $$q \rightarrow 1$$ ) at larger $$|\eta |$$ , while mid- $$\eta$$ particles ( $$|\eta | \approx 0$$ ) approach near-equilibrium behavior. Parameter correlations, particularly between $$T_0$$ , $$\langle \beta _T\rangle$$ , $$q$$ , and $$\langle p_T \rangle$$ , highlight interplay between thermal and collective-like dynamics. The results provide critical insights into the interplay of thermalization, effective flow, and non-equilibrium effects in small collision systems, advancing the understanding of bulk hadronic matter in high-energy $$pp$$ interactions. |
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| ISSN: | 2045-2322 |