用于固定靶碰撞中开粲与美产生的Pythia8调谐方案

中文摘要 AI 辅助

我们提出FTFT（固定靶碎裂调谐方案），这是一组针对质心系能量√s≈20-42GeV的固定靶碰撞中粲与美强子产生优化的Pythia8参数。该能区中精确的重味产生对于预测SHiP等束流 dump 实验的中微子通量与隐粒子产额是必要的。该调谐分两阶段推导：第一阶段，将D介子的费曼x（x_F）、横动量平方（p_T²）、电荷或领头粒子产生不对称性的微分分布，拟合至π束与质子束固定靶实验的数据；第二阶段，从 inclusive 粲截面测量中提取各束流的K因子，以将模拟截面缩放至测量数据。拟合得到的粲碎裂与多部分子相互作用参数偏离标准LHC调谐的默认值，与早期固定靶研究结果一致。

英文摘要

We present FTFT (Fixed-Target Fragmentation Tune), a set of Pythia8 parameters optimised for the production of charm and beauty hadrons in fixed-target collisions at centre-of-mass energies $\sqrt{s} \simeq 20-42$ GeV. Accurate heavy-flavour production in this regime is needed to predict neutrino fluxes and hidden-particle yields at beam-dump experiments such as SHiP. The tune is derived in two stages. First, differential distributions in Feynman-$x$ ($x_F$), transverse momentum squared ($p_T^2$), and charge or leading-particle production asymmetry of $D$ mesons are fitted to data from pion- and proton-beam fixed-target experiments. Second, $K$-factors for each beam are extracted from inclusive charm cross-section measurements to scale the simulated cross section to the measured data. The fitted charm-fragmentation and multiparton-interaction parameters depart from standard LHC-tuned defaults, in line with earlier fixed-target studies.

发表机构

• Ghent University（根特大学）

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