How to test path-length dependence in energy loss mechanisms: analysis leading to a new observable

Abstract

When traversing QCD medium, high $p_{\perp }$ partons lose energy, which is typically measured by suppression, and also predicted by various energy loss models. A crucial test of different energy loss mechanisms is how the energy loss depends on the length of traversed medium (so-called path-length dependence). The upcoming experimental results will allow to, at least in principle, for the first time, clearly observe how the energy loss changes with the size of the medium, in particular, by comparing already available $Pb+Pb$ measurements with now upcoming $Xe+Xe$ data at the LHC. However, in practice, to actually perform such test, it becomes crucial to chose an optimal observable. With respect to this, a ratio of observed suppression for the two systems may seem a natural (and frequently mentioned) choice. We, however, show that extracting the path-length dependence from this observable would not be possible. We here provide an analytical derivation based on simple scaling arguments, as well as detailed numerical calculations based on our advanced energy loss framework, showing that a different observable is suitable for this purpose. We call this observable path-length sensitive suppression ratio ($R_L^{AB}$) and provide our predictions before experimental data become available. This predictions also clearly show that this observable will allow a simple comparison of the related theoretical models with the experimental data, and consequently to distinguish between different (underlying) energy loss mechanisms, which is in turn crucial for understanding properties of created QCD medium.

arXiv comment4 pages, 3 figures

References in corpus (43)

• New Forms of QCD Matter Discovered at RHIC
• Radiative energy loss of high energy quarks and gluons in a finite volume quark-gluon plasma
• Fully quantum treatment of the Landau--Pomeranchuk--Migdal effect in QED and QCD
• Reaction Operator Approach to Non-Abelian Energy Loss
• What RHIC Experiments and Theory tell us about Properties of Quark-Gluon Plasma ?
• Multiple Parton Scattering in Nuclei: Parton Energy Loss
• Global analysis of fragmentation functions for pions and kaons and their uncertainties
• Extracting jet transport coefficient from jet quenching at RHIC and LHC
• Photon Emission from Ultrarelativistic Plasmas
• Effective Kinetic Theory for High Temperature Gauge Theories
• The theory and phenomenology of perturbative QCD based jet quenching
• Medium-Induced Gluon Radiation off Massive Quarks Fills the Dead Cone
• Charged-particle nuclear modification factors in PbPb and pPb collisions at sqrt(s[NN]) = 5.02 TeV
• A light-cone wavefunction approach to open heavy flavor dynamics in QCD matter
• Transverse momentum spectra and nuclear modification factors of charged particles in pp, p-Pb and Pb-Pb collisions at the LHC
• Jet Tomography of Au+Au Reactions Including Multi-gluon Fluctuations
• Collisional Energy Loss in a Finite Size QCD Matter
• Radiative energy loss in a finite dynamical QCD medium
• Hydrodynamic predictions for 5.44 TeV Xe+Xe collisions
• Charm Cross Sections for the Tevatron Run II
• Centrality and pseudorapidity dependence of the charged-particle multiplicity density in Xe-Xe collisions at $\sqrt{s_{\mathrm{NN}}}$ = 5.44 TeV
• Comparing energy loss and $p_{\perp }$-broadening in perturbative QCD with strong coupling $\mathcal{N}=4$ SYM theory
• LHC jet suppression of light and heavy flavor observables
• Theoretical formalism of radiative jet energy loss in a finite size dynamical QCD medium
• Azimuthal jet flavor tomography with CUJET2.0 of nuclear collisions at RHIC and LHC
• Nuclear modification of high transverse momentum particle production in p+A collisions at RHIC and LHC
• DREENA-B framework: first predictions of $R_{AA}$ and $v_2$ within dynamical energy loss formalism in evolving QCD medium
• Heavy flavor suppression predictions at 5.1 TeV Pb+Pb collisions at LHC
• Cracking the difference of estimating heavy quark transport coefficients in a Quark-Gluon Plasma
• Jet quenching in the strongly-interacting quark-gluon plasma
• Cumulants and nonlinear response of high $p_T$ harmonic flow at $\sqrt{s_{NN}}=5.02$ TeV
• Constraining the Physics of Jet Quenching
• Generalization of radiative jet energy loss to non-zero magnetic mass
• Predictions for multiplicities and flow harmonics in 5.44 TeV Xe+Xe collisions at the CERN Large Hadron Collider
• Constraints on the Path-Length Dependence of Jet Quenching in Nuclear Collisions at RHIC and LHC
• Event-by-event $v_n$ correlations of soft hadrons and heavy mesons in heavy ion collisions
• Perspectives for the study of charm in-medium quenching at the LHC with ALICE
• Toward a consistent evolution of the quark-gluon plasma and heavy quarks
• Charged-particle nuclear modification factors in XeXe collisions at $\sqrt{s_{\mathrm{NN}}}$ = 5.44 TeV
• Energy loss in a fluctuating hydrodynamical background
• Calculating hard probe radiative energy loss beyond soft-gluon approximation: Examining the approximation validity
• Interplay between bulk medium evolution and (D)GLV energy loss
• Complex suppression patterns distinguish between major energy loss effects in Quark-Gluon Plasma

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• Progress in the Glauber model at collider energies
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• Statistical analysis of pQCD energy loss across system size, flavor, $\sqrt{s_{NN}}$, and $p_T$
• Utilizing high-$p_{\perp }$ theory and data to constrain the initial stages of quark-gluon plasma
• Modification of charged-particle jets in event-shape engineered Pb$-$Pb collisions at $\sqrt{s_{\mathrm{NN}}}=5.02$ TeV
• Dynamical energy loss formalism: from describing suppression patterns to implications for future experiments
• Considerations on the suppression of charged particles and ${\pi }^0$ in high energy heavy ion collisions
• Understanding mass hierarchy in collisional energy loss through heavy flavor data
• Predictions for photon-jet correlations at forward rapidities in heavy-ion collisions
• Quenching of heavy and light flavour jets: experimental overview
• From high $p_{\perp }$ theory and data to inferring anisotropy of Quark-Gluon Plasma