Speaker
Zhenyu Chen
(Rice University (US))
Description
Observation of a long-range, near-side, two-particle correlation (known as the “Ridge”) in high-multiplicity pp and pPb collisions opened up new opportunities of exploring novel QCD dynamics in small collision systems. While extensive studies of this long-range correlation phenomenon in pPb collisions have revealed its collective properties, the nature of the ridge in pp collisions still remains unknown. New measurements of two-particle angular correlations for charged particles, and identified $K^0_s$ and $\Lambda$ particles emitted in 7 TeV pp collisions are presented using the CMS detector. With the implementation of a high-multiplicity trigger during the 2010 LHC pp run, CMS is capable of probing the most exotic high multiplicity pp collisions. The second-order ($v_2$) and third-order ($v_3$) anisotropy harmonics of charged particles, $K^0_s$ and $\Lambda$ particles are extracted from long-range correlations as a function of particle multiplicity and $p_T$, after correcting for the contribution of back-to-back jet correlations. Four-particle cumulants ($c_2${4}) are also measured for charged particles as a function of multiplicity. The results are compared to 5.02 TeV pPb data covering a similar range of particle multiplicity. These new studies will provide stringent constraints on the possible origin of long-range correlations observed in small collision systems.
| On behalf of collaboration: | CMS |
|---|
Primary author
Zhenyu Chen
(Rice University (US))
