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Wei-Xi Kong

Publications and source records attributed to Wei-Xi Kong.

3 recordsLinked to original sources

Suppression of elliptic anisotropy inside jets: A new perspective for jet quenching

Particle azimuthal anisotropies inside jets, defined within the momentum plane perpendicular to the jet axis, carry the information of the QCD cascade process for jet formation. In this work, we propose to measure the medium-induced modifications of the elliptic anisotropy inside jets in relativistic heavy-ion collisions to provide novel insight into the jet quenching phenomenon. By simulating the jet propagation in the hot and dense nuclear medium with a Linear Boltzmann Transport model, we observe a de-correlation in the two-particle azimuthal angular distribution for inclusive jet production in AA collisions relative to that in pp collisions, which results in significant suppression of the in-jet elliptic anisotropy coefficient $v_2$. This phenomenon arises from the stochastic and strong interactions with the thermal QGP medium undergone by the jet particles. Furthermore, the nuclear modifications of the in-jet $v_2$ are found to be sensitive to the medium properties in the model study, which provide a potential probe for the jet tomography of nuclear matter.

hep-ph

The Fox-Wolfram Moment of Jet Production in Relativistic Heavy Ion Collisions

We present the first theoretical investigation of Fox-Wolfram moments (FWMs) for multi-jet production in relativistic heavy ion collisions. In this work, jet productions in p+p collisions are computed with a Monte Carlo event generator SHERPA, while the Linear Boltzmann Transport model is utilized to simulate the multiple scattering of energetic partons in the hot and dense QCD matter. The event-normalized distributions of the lower-order FWM, $H_1^T$ in p+p and Pb+Pb collisions are calculated. It is found that for events with jet number $n_\text{jet} = 2$ the $H_1^T$ distribution in Pb+Pb is suppressed at small $H_1^T$ while enhanced at large $H_1^T$ region as compared to p+p. For events with $n_\text{jet}>2$, the jet number reduction effect due to jet quenching in the QGP decreases the $H_1^T$ distribution at large $H_1^T$ in Pb+Pb relative to p+p. The medium modification of the Fox-Wolfram moment $H_1^T$ for events with $n_\text{jet}\ge 2$ are also presented, which resemble those of events with $n_\text{jet} = 2$. Its reason is revealed through the relative contribution fractions of events with different final-state jet numbers to $H_1^T$.

hep-ph

Medium modifications of heavy-flavor jet angularities in high-energy nuclear collisions

We present the first theoretical study of heavy-flavor jet angularities ($λ^κ_α$) in Pb+Pb collisions at $\sqrt{s_{\rm NN}}=$ 5.02 TeV. The initial production of heavy-flavor jets is carried out using the POWHEG+PYTHIA8 prescription, while the jet evolution in the quark-gluon plasma (QGP) is described by the SHELL transport model. In p+p collisions, we observe narrower angularity distributions for D$^0$-tagged jets compared to inclusive jets, consistent with the ALICE preliminary results. We then demonstrate that jet quenching in the QGP slightly widens the angularity distribution of D$^0$-tagged jets in Pb+Pb collisions relative to that in p+p collisions for jet transverse momentum of $10 < p_{\rm T,jet} < 20$ GeV/c, while the angularity distributions of inclusive and D$^0$-tagged jets become narrower in Pb+Pb collisions relative to p+p at $p_{\rm T,jet} > 20$ GeV/c due to the strong influence of the selection bias. Additionally, by comparing the average angularities $\langle λ^κ_α \rangle$ of inclusive, D$^0$-tagged and B$^0$-tagged jets with varying $α$ and $κ$, we show that the larger the quark mass is, the lower the jet's $\langle λ^κ_α \rangle$ values are. As a result of the slenderer initial distribution, we predict that as compared to inclusive jets, the heavy-flavor jets, especially the B$^0$-tagged ones, will suffer stronger modifications of $\langle λ^κ_α \rangle$ in Pb+Pb relative to p+p at $10 < p_{\rm T,jet} < 20$ GeV/c. For a larger jet radius, a more significant broadening of jet angularities is predicted because of the enhanced contributions of the wide-angle particles.

hep-ph