Turkish Journal of Physics




In the current analysis we have reported the spectra of average transverse-sphericity as a function of multiplicity ($N_ch$) in $pp$ collisions for primary charged particles ($\pi^{+}, \pi^{-}, K^+, K^-, p$ and $\bar{p}$) in mid pseudo-rapidity of $ \eta < 0.8$ and in the kinematic transverse momentum range of $p_T > 0.5 \; GeV/c$ at $\sqrt{s_{NN}}$ = 0.9 and $7 \,TeV$. Two Monte Carlo event generators have been used for current analysis and the predictions of the model are compared to the results coming from the ALICE experiment based at the LHC. A detailed analysis has been carried out for three types of events (soft events, hard events and bulk events) categorized by the transverse momentum ($p_T$) of the charged particles.It is observed that the predictions of model, underestimate ALICE data at larger values of $N_{ch}$ while at the low values of $N_{ch}$, the calculated values of model are close to ALICE data. The predictions at 0.9 TeV explain ALICE data well. At large values of $N_{ch}$, the models predominantly produce hard events as compared with those perceived from ALICE data. This variance can be observed in the bulk event class, as event generators produce more hard events, whereas experiment gives more soft events. At high multiplicity, the generators underestimate the production of isotropic events. The event generators favor the production of back to back jets (high-$p_T$ jets, low $$) and also generate large multiplicity events.


Average transverse sphericity, pseudorapidity, PYTHIA8, EPOS-LHC, multiplicity

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