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arXiv 2007.02208nucl-exhep-ex
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$\sqrt{s}$ = 7 TeV pp碰撞中$ω$介子的产生

Production of $ω$ mesons in pp collisions at $\sqrt{s}$ = 7 TeV

ALICE Collaboration

摘要:

在LHC上用ALICE探测器测量了在2 < $p_{\rm{T}}$ < 17 GeV/$|y|<0.5$的横向动量范围内,$\sqrt{s}$ = 7 TeV的pp碰撞中快度包含$ω(782)$介子产生的不变微分截面.通过$ω\rightarrowπ^+π^-π^0$衰变通道重建了$ω$介子。测量的$ω$产生截面与各种计算进行比较:PYTHIA 8.2 Monash 2013描述了数据,而PYTHIA 8.2 Tune 4C高估了约50%的数据。最近的NLO计算,其中包括一个模型描述的整个矢量介子九重的碎裂,描述的数据低于6 GeV/ $c$的不确定性,而它高估了高达50%的数据为更高的$p_{\rm{T}}$。的$ω/π^0$比是在协议与以前的测量在较低的碰撞能量和PYTHIA计算。此外,该测量与测量的$p_{\rm{T}}$范围内的横向质量缩放兼容,并且该比率是恒定的,其中$C^{ω/π^{0}}$ = 0.67 $\pm$ 0.03(stat)$\pm$ 0.04(sys)高于2.5 GeV/ $c$的横向动量。

英文摘要:

The invariant differential cross section of inclusive $ω(782)$ meson production at midrapidity ($|y|<0.5$) in pp collisions at $\sqrt{s}$ = 7 TeV was measured with the ALICE detector at the LHC over a transverse momentum range of 2 < $p_{\rm{T}}$ < 17 GeV/$c$. The $ω$ meson was reconstructed via its $ω\rightarrowπ^+π^-π^0$ decay channel. The measured $ω$ production cross section is compared to various calculations: PYTHIA 8.2 Monash 2013 describes the data, while PYTHIA 8.2 Tune 4C overestimates the data by about 50%. A recent NLO calculation, which includes a model describing the fragmentation of the whole vector-meson nonet, describes the data within uncertainties below 6 GeV/$c$, while it overestimates the data by up to 50% for higher $p_{\rm{T}}$. The $ω/π^0$ ratio is in agreement with previous measurements at lower collision energies and the PYTHIA calculations. In addition, the measurement is compatible with transverse mass scaling within the measured $p_{\rm{T}}$ range and the ratio is constant with $C^{ω/π^{0}}$ = 0.67 $\pm$ 0.03 (stat) $\pm$ 0.04 (sys) above a transverse momentum of 2.5 GeV/$c$.

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