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arXiv 2202.01548nucl-exhep-ex
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在$\sqrt{s} = 13$ TeV pp碰撞中带电粒子喷流产生的多重数依赖性

Multiplicity dependence of charged-particle jet production in pp collisions at $\sqrt{s} = 13$ TeV

ALICE Collaboration

摘要:

首次研究了在$\sqrt{s} = 13\ \mathrm{TeV}$质心能量下pp碰撞中喷流产生的多重数依赖性。使用反$k_\mathrm{T}$算法从带电粒子重构射流,其中分辨率参数$R$从$0.2$变化到$0.7$。在赝快度范围$|η_{\rm jet}|< 0.9-R$和横向动量范围$5<p_\mathrm{T,jet}^{\rm ch}<140\ \mathrm{GeV}/c$中测量喷流。多重性区间由ALICE前向检测器V0分类。将带电粒子喷流的$p_{\mathrm{T}}$微分截面与首阶(LO)和次首阶(NLO)微扰量子色动力学(pQCD)计算进行了比较。结果发现,数据更好地描述了NLO计算,虽然NLO预测高估了射流截面低于$20\ \mathrm{GeV}/c$。还测量了不同$R$的横截面比,并与模型计算进行了比较。这些测量提供了深入了解射流破碎的角度依赖性。射流产率随着自归一化带电粒子多重性的增加而增加。这种增加表明,只有在最高的多重性射流的横向动量和分辨率参数的依赖性很弱。虽然这种行为是定性描述的PYTHIA目前的版本,定量描述可能需要实施新的机制,在强子碰撞多粒子生产。

英文摘要:

The multiplicity dependence of jet production in pp collisions at the centre-of-mass energy of $\sqrt{s} = 13\ \mathrm{TeV}$ is studied for the first time. Jets are reconstructed from charged particles using the anti-$k_\mathrm{T}$ algorithm with resolution parameters $R$ varying from $0.2$ to $0.7$. The jets are measured in the pseudorapidity range $|η_{\rm jet}|< 0.9-R$ and in the transverse momentum range $5<p_\mathrm{T,jet}^{\rm ch}<140\ \mathrm{GeV}/c$. The multiplicity intervals are categorised by the ALICE forward detector V0. The $p_{\mathrm{T}}$ differential cross section of charged-particle jets are compared to leading order (LO) and next-to-leading order (NLO) perturbative quantum chromodynamics (pQCD) calculations. It is found that the data are better described by the NLO calculation, although the NLO prediction overestimates the jet cross section below $20\ \mathrm{GeV}/c$. The cross section ratios for different $R$ are also measured and compared to model calculations. These measurements provide insights into the angular dependence of jet fragmentation. The jet yield increases with increasing self-normalised charged-particle multiplicity. This increase shows only a weak dependence on jet transverse momentum and resolution parameter at the highest multiplicity. While such behaviour is qualitatively described by the present version of PYTHIA, quantitative description may require implementing new mechanisms for multi-particle production in hadronic collisions.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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