Full jet in quark-gluon plasma with hydrodynamic medium response

We study the nuclear modifications of full jets and their structures in relativistic heavy-ion collisions, including the effect of hydrodynamic medium response to jet quenching. To study the evolutions of the full jet shower and the traversed medium with energy and momentum exchanges between them, we formulate a coupled jet-fluid model consisting of a set of jet transport equations and relativistic hydrodynamics equations with source terms. In our model, the full jet shower interacts with the medium and gets modified via collisional and radiative processes during the propagation. Meanwhile, the energy and momentum are deposited from the jet shower to the medium and then evolve with the medium hydrodynamically. The full jet defined by a cone size in the final state includes the jet shower and the particles produced from jet-induced flow. We apply our model to calculate the full jet energy loss and the nuclear modifications of jet rate and shape in Pb+Pb collisions at $2.76A\mathrm{TeV}$. It is found that the inclusion of jet-induced flow contribution leads to stronger jet-cone size dependence for jet energy loss and jet suppression. Jet-induced flow also has a significant contribution to jet shape function and dominates at large angles away from the jet axis.

Figure 1

Energy density distribution of the medium in the transverse plane at midrapidity ${\eta }_{\mathrm{s}}=0$ at different proper times $\tau =3.0$, 7.5, and $12\mathrm{fm}/c$. The jet with the initial $p_T^{\mathrm{jet}}=150\mathrm{GeV}/c$ is produced at $(x_0^{\mathrm{jet}},y_0^{\mathrm{jet}})=(0\mathrm{fm},6.54\mathrm{fm})$ and propagates in the direction of ${\varphi }_p=5\pi /8$. The left panels (a-1), (a-2), and (a-3) show the whole medium energy density, and the right panels (b-1), (b-2), and (b-3) show the medium energy density subtracted by that in the case without jet propagation.

Figure 2

Total $p_T$ loss for jets in central Pb+Pb collisions at $2.76A$ TeV as a function of initial jet $p_T$ for the cone sizes (a) $R=0.2$, 0.3, and 0.4 and (b) $R=0.3$, 0.6, and 0.9. The solid lines are for jets with the hydro part, and the dashed lines are for jets without the hydro part.

Figure 3

Nuclear modification factor $R_{\mathrm{AA}}$ for inclusive jet spectrum in central Pb+Pb collisions at $2.76A\mathrm{TeV}$ with jet-cone sizes (a) $R=0.2$, 0.3, and 0.4 and (b) $R=0.3$, 0.6, and 0.9. The solid lines are the results for inclusive jets with the hydro part, and the dashed lines are for those without the hydro part. The turquoise plus markers, the magenta circles, and the orange triangles show the experimental data taken from the CMS Collaboration [23] for the jet-cone sizes $R=0.2$, 0.3, and 0.4, respectively. The colored shaded boxes indicate the systematic uncertainties of the same colored data points.

Figure 4

(a) Jet shape function for inclusive jets with $p_T^{\mathrm{jet}}>100\mathrm{GeV}/c$ in central Pb+Pb and $p+p$ collisions at $2.76A\mathrm{TeV}$. (b) Nuclear modification factor for jet shape function for inclusive jets with $p_T^{\mathrm{jet}}>100\mathrm{GeV}/c$ in central Pb+Pb collisions. The solid and dashed lines are results for jets with and without the hydro part. The dotted line is the pythia simulation, and the turquoise triangles are data for $p+p$ collisions (left panel). The black circles are data for Pb+Pb collisions, with the shaded boxes indicating the systematic uncertainties. Data are taken from the CMS Collaboration [24].

Figure 5

Jet shape function for single inclusive jets with $p_T^{\mathrm{jet}}>100\mathrm{GeV}/c$ in central Pb+Pb and $p+p$ collisions at $2.76A\mathrm{TeV}$. The solid and dashed lines are results for jets with and without the hydro part, and the dash-dotted line shows the pure hydro part contribution. The dotted line is the pythia simulation, and the turquoise triangles are data for $p+p$ collisions. The black circles are data for Pb+Pb collisions, with the shaded boxes indicating the systematic uncertainties. Data are taken from the CMS Collaboration [24].

Figure 6

Jet shape function for (a) leading and (b) subleading jets in dijet events in central Pb+Pb collisions and in $p+p$ collisions at $2.76A\mathrm{TeV}$. The leading jet has $p_{T,1}^{\mathrm{jet}}>120\mathrm{GeV}/c$, the subleading jet has $p_{T,2}^{\mathrm{jet}}>50\mathrm{GeV}/c$, and the azimuthal angle between the leading and subleading jets is $\mathrm{\Delta }{\phi }_{1,2}>5\pi /6$. The solid and dashed lines are results with and without the hydro part contribution in central Pb+Pb collisions, respectively. The dashed dotted line shows the pure hydro part contribution. The dotted line is the result for $p+p$ collisions obtained from pythia. The black circles are data in central (0–$30\%$) Pb+Pb collisions from the CMS Collaboration [28], with the shaded boxes indicating the systematic uncertainties.