Measurements of the substructure of high-momentum jets produced in proton-proton (pp) collisions give insight into fundamental aspects of QCD, from the production of highly virtual partons, to their subsequent radiation and hadronization. Additionally, once the evolution of jets in vacuum is calibrated, it is possible to study potential modification to jet substructure due to interaction with the cold nuclear medium present in proton-gold (pAu) collisions.
Abstract: Relativistic heavy-ion collisions are a unique tool that allow us to probe QCD and its fundamental interactions; of particular interest is the phase transition between a hadron gas and a quark-gluon plasma (QGP). Characterizing this phase transition and mapping out the QCD phase diagram have been some of the primary goals of relativistic heavy-ion collisions over the past two decades. This talk will cover the background of the QGP and discuss a selection of the important observations over the past 22 years of RHIC operations relating to the QCD phase diagram.
Neutrino experimentation is an important pathway to physics beyond the standard model, raising questions on how neutrinos obtain their vanishingly small but non-zero mass, what that mass is, and if they are their own antiparticle. Antineutrinos, as an abundant product of nuclear decay chains, are also important to advancing our understanding of nuclear physics and verifying nuclear databases.
Precision Timing information at the level of 10-30ps is a game changer for detectors at future collider experiments. For example, the ability to assign a timestamp with 30ps precision to particle tracks will mitigate the impact of pileup at the High-Luminosity LHC (HL-LHC). With a time spread of the beam spot of approximately 180ps, a track time resolution of 30ps allows for a factor of 6 reduction in pileup. HL-LHC will only be the first in HEP experiments to exploit the concept of 4D tracking using time as one of the parameters.
Please join us at 3 p.m. on Monday, May 16 in the Wright Lab Vault for a brief celebration with some birthday cake and a toast to mark the 5th anniversary of the official opening of Wright Lab. We look forward to seeing you there!
Jet declustering techniques have brought up the possibility to access the Lund plane of QCD emissions in jets. By scanning different areas of the Lund jet plane, sensitivity to different physics effects can be enhanced, including quark mass effects. In this talk I will discuss the techniques and the measurement by ALICE (Nature 605, 440-446 (2022)) of the first direct signature of the dead cone effect in QCD. I will also discuss the problematics of the Lund plane in heavy ion collisions and prospects.
Collective quantum effects should play a significant role in the formation of hadrons from a deconfined and chirally symmetric state of matter. Yet most of our models ignore these effects or treat them as corrections after the dynamic calculation (e.g. color reconnection effects in PYTHIA). I will try to show that there is a direct connection between the entanglement entropy in the initial state and the thermodynamic entropy in the final state at least for elementary collisions where not too many decoherence effects are expected.
We investigate the impact of soft gluon resummation on the azimuthal angle correlation between the total and relative momenta of two energetic final state particles (jets). We show that the initial and final state radiations induce sizable cos(ϕ) and cos(2ϕ) asymmetries in single jet and dijet events, respectively.
Join us on April 22nd from 10:30am-12pm in ESC 110 (21 Sachem St.) for a moderated panel followed by small group discussions on nuclear weapons.
Microspheres have been the first objects optically levitated by Arthur Ashkin in the 1970s. While the technology itself was successfully used to trap atoms to explore new physics, the actual utilization of microspheres and other macroscopic objects as a useful tool for physics has emerged in the recent years. The unique properties of those levitated objects allows to deploy them as sensors with unmatched properties and advantages.