arXiv subjects

Ben Bert

Publications and source records attributed to Ben Bert.

4 recordsLinked to original sources

arXiv2026

Jet Quenching in the Smallest Hadronic Collision Systems

We present perturbative quantum chromodynamics (pQCD) predictions for high-momentum particle yield modification in very light ion collisions - ${}^{10}\mathrm{B}+{}^{10}\mathrm{B}$, ${}^{6}\mathrm{Li}+{}^{6}\mathrm{Li}$, ${}^{4}\mathrm{He}+{}^{4}\mathrm{He}$, and ${}^{3}\mathrm{He}+{}^{3}\mathrm{He}$ - with and without medium-induced energy loss. We find non-trivial suppression in symmetric systems from ${}^{208}\mathrm{Pb}+{}^{208}\mathrm{Pb}$ to ${}^{3}\mathrm{He}+{}^{3}\mathrm{He}$ and in asymmetric $A+B$ systems, with the suppression scaling approximately as $R_{AB} \simeq (\sqrt{AB})^{1/3}$. Further, we find that ${}^{3}\mathrm{He}$ and ${}^{6}\mathrm{Li}$ offer particularly clean environments for observing final-state partonic energy loss from quark-gluon plasma (QGP) formation in extremely small systems. Finally, we show that energy loss models generically predict $v_2\{\mathrm{SP}\} \approx 0$ in small systems, indicating that the large measured $v_2 > 0$ in $p+{}^{208}\mathrm{Pb}$ is not due to energy loss.

hep-ph↗

arXiv2026

Energy loss predicts no $v_2$ in small systems

We present high-$p_T$ $R_{AB}$ and $v_2$ from a perturbative quantum chromodynamics-based energy loss model that includes event-by-event hydrodynamic evolution of the medium and small system size corrections to the energy loss. The model is calibrated on, and describes well, large system $R_{AA}$ and $v_2$ experimental data. The extrapolation of our model to $\mathrm{Ne}+\mathrm{Ne}$ and $\mathrm{O}+\mathrm{O}$ agrees quantitatively with recent experimental measurements of $R_{AA}$. Surprisingly, at high-$p_T$ our energy loss model predicts $v_2\approx0$ for all symmetric and asymmetric small systems when extracted using either hard-hard or hard-soft two-particle correlations. We argue that all energy loss models will in general predict $v_2\approx0$ when extracted using hard-soft correlations, which is the usual experimental method for measuring anisotropy in hadronic collisions, due to a generic geometric decorrelation between the hard and soft sector participant planes.

hep-ph↗

arXiv2025

From Lead to Helium: Discovery Potential for Jet Quenching in the Smallest Collision Systems

We present perturbative quantum chromodynamics (pQCD) predictions for the modification to the yield of high-momentum particles in very light ion collisions - ${}^{10}\mathrm{B} + {}^{10}\mathrm{B}$, ${}^{6}\mathrm{Li} + {}^{6}\mathrm{Li}$, ${}^{4}\mathrm{He} + {}^{4}\mathrm{He}$, and ${}^{3}\mathrm{He} + {}^{3}\mathrm{He}$ - both with and without medium-induced energy loss. We show that there is non-trivial suppression expected from our partonic energy loss model in symmetric systems from ${}^{208}\mathrm{Pb} + {}^{208}\mathrm{Pb}$ to ${}^{3}\mathrm{He} + {}^{3}\mathrm{He}$ and in asymmetric systems $A + B$, and that the energy loss scales approximately with $(\sqrt{A B})^{1 / 3}$. Further, we find that deep inelastic scattering measurements in ${}^{3}\mathrm{He}$ and ${}^{6}\mathrm{Li}$ tightly constrain the nPDF baseline, making these isotopes a particularly clean environment for observing final-state partonic energy loss induced by the formation of a quark-gluon plasma in these very small systems.

hep-ph↗

arXiv2025

Integrable Non-Holonomic Constraints and Gauge Fixing in Classical Field Theory

We re-examine the derivation of the equations of motion from an action principle for classical field theories with non-holonomic constraints, \textit{i.e.}, constraints involving derivatives of the fields. We find that the usual method for gauge fixing in classical and quantum field theories is highly non-trivial for non-holonomic gauge constraints, such as the Coulomb and Lorenz gauges. The subtlety appears at the use of the so-called transposition rule, $\delta(\partial_\nu A^\mu)=\partial_\nu(\delta A^\mu)$, which has been shown not to hold for general non-holonomic constraints in the point-particle context. We provide a sufficient definition of integrable non-holonomic constraints in classical field theory that allows us to prove that the transposition rule holds for all theories with these constraints; we are then able to recover the usual treatment of gauge fixing for gauges of this type.

hep-th↗