Hard Probe 2016

Jet transverse fragmentation momentum from h-h correlations in pp and p-Pb collisions

24 Sept 2016, 10:40

20m

Shi-Yan Hall (East Lake International Convention Center)

Parallel Session II: Hard Probes in p+p and p+A Collisoions (II)

Speaker

Jussi Viinikainen (University of Jyvaskyla (FI))

Description

QCD color coherence phenomena, like angular ordering, can be studied by looking at jet fragmentation. As the jet is fragmenting, it is expected to go through two different phases. First, there is QCD branching that is calculable in perturbative QCD. Next, the produced partons hadronize in an non-perturbative way in a hadronization process. The jet fragmentation can be efficiently studied using the method of two particle correlations. A useful observable is the jet transverse fragmentation momentum $j_{\mathrm{T}}$, which describes the angular width of the jet. Previously for example the CCOR and PHENIX collaborations have measured $\sqrt{⟨j_{\mathrm{T}}^2⟩}$ in pp collisions and they have found no dependence on trigger $p_{\mathrm{T}}$. These results have been interpreted to reflect a universality in the jet hadronization process. However, they determine only a single value for $j_{\mathrm{T}}$ and therefore mix the two processes mentioned above. In this contribution, a more differential study will be presented in which separate $j_{\mathrm{T}}$ components for branching and hadronization will be distinguished from the data measured by the ALICE experiment. The $p_{\mathrm{T}\mathrm{t}}$ dependence of the hadronization component $\sqrt{⟨j_{\mathrm{T}}^2⟩}$ is found to be rather flat, as suggested by previous measurements. However, the branching component shows slightly rising trend in $p_{\mathrm{T}\mathrm{t}}$. The data from $\sqrt{s}=7\text{TeV}$ pp and $\sqrt{s_{\mathrm{N}\mathrm{N}}}=5.02\text{TeV}$ p-Pb collisions will also be compared to the results obtained from PYTHIA8 simulations.

Presentation materials

jussi_jt_HardProbes2016.pdf