FEB
16
Tuesday
Nuclear Physics Seminar
"Precision Jet Physics to Probe Strong Dynamics"
Presented by Dr. Daekyoung Kang, Los Alamos National Laboratory
11 am, Small Seminar Room, Bldg. 510
Tuesday, February 16, 2016, 11:00 am
Hosted by: Oleg Eyser
Jets produced in the high energy collision of quarks and gluons at colliders are bunches of collimated particles traveling along the same direction. Jet productions are extensively studied in various colliders in search for new physics beyond the standard model and as a probe of new state of matter like QGP. In this talk, I will discuss jet study at a high precision as a new tool to probe strong dynamics in electron-proton collider. As an example, I will show the new tool can be used to determine the strong coupling constant and to improve our understanding of nuclear structure such as a parton distribution function of proton. With new level of precision not previously available for jets, the jet physics will provide one of milestones at the early stage of future Electron-Ion collider.
FEB
16
Tuesday
Physics Colloquium
"Physics opportunities at future circular colliders"
Presented by LianTao Wang, University of Chicago
3:30 pm, Large Seminar Room, Bldg. 510
Tuesday, February 16, 2016, 3:30 pm
Hosted by: Robert Pisarski
Following the discovery of the Higgs boson, there has been a lot discussion about the next step in high energy physics. Among different options, a couple of newly proposed next generation circular colliders, including FCC at CERN and CEPC/SPPC in China, have attracted a lot of attention. Through preliminary studies in the past couple of years, an exciting picture of their physics capabilities has emerged. In this talk, I will give an overview on this topic, focusing on some of the most important questions in high energy physics they can help addressing
FEB
19
Friday
Nuclear/Riken Theory Seminar
"The Transverse Structure of the Nucleon"
Presented by Marc Schlegel, University of Tuebingen
11 am, Small Seminar Room, Bldg. 510
Friday, February 19, 2016, 11:00 am
Hosted by: Soeren Schlichting
Perturbative QCD based on the Parton Model of the nucleon is a very successful theoretical approach to describe high-energy processes at particle accelerators and colliders. In particular, parton distribution functions are key ingredients of this approach and give information on the partonic substructure of the nucleon. As such they deliver a one-dimensional picture of how the parton momenta are distributed in the nucleon. In this talk extensions of the parton model are presented which provide access to more detailed information on the dynamics of partons in the nucleon. In particular observables involving transversely polarized nucleons are discussed. They can be described in terms of dynamical quark-gluon correlations which in turn can be studied at an Electron-Ion Collider. Another extension of the parton model takes into account the intrinsic transverse motion of the partons. In this approach - called Transverse Momentum Dependent (TMD) factorization - one can study three-dimensional distributions of the parton momenta. In addition, implications of the transverse motion of gluons in the nucleon will be discussed for LHC physics.
FEB
19
Friday
Nuclear Theory/RIKEN Seminar
"Lattice QCD investigations of quark transverse momentum in hadrons"
Presented by Michael Engelhardt, New Mexico State University
2 pm, Small Seminar Room, Bldg. 510
Friday, February 19, 2016, 2:00 pm
Hosted by: Soeren Schlichting
An ongoing program of evaluating transverse momentum dependent parton distributions (TMDs) within lattice QCD is reviewed, summarizing recent progress with respect to several challenges faced by such calculations. These lattice calculations are based on a definition of TMDs through hadronic matrix elements of quark bilocal operators containing staple-shaped gauge connections. A parametrization of the matrix elements in terms of invariant amplitudes serves to cast them in the Lorentz frame preferred for a lattice calculation. Results presented include data on the naively T-odd Sivers and Boer-Mulders effects, as well as the transversity and a worm-gear distribution. Correlating quark transverse momentum with impact parameter, one can extract quark orbital angular momentum directly,including both the Ji as well as the Jaffe-Manohar definitions.
FEB
26
Friday
Nuclear Theory/RIKEN Seminar
"Real time method of thermal field theory"
Presented by Samir Mallik, Saha Institute of Nuclear Physics
2 pm, Small Seminar Room, Bldg. 510
Friday, February 26, 2016, 2:00 pm
Hosted by: Soeren Schlichting
I review the basic ideas of real time formulation of thermal field theory. Then I like to consider the following topics in this formulation: 1) thermal propagator for a scalar field 2) spectral representation of two-point functions for arbitrary fields 3) perturbation expansion 4) one-loop self -energy 5) dilepton production
MAR
18
Friday
Nuclear Theory/RIKEN Seminar
"Duality, Dimensions and Reduction on the Lattice"
Presented by Joel Giedt, Rensselaer Polytechnic Institute
2 pm, Small Seminar Room, Bldg. 510
Friday, March 18, 2016, 2:00 pm
Hosted by: Soeren Schlichting
Montonen and Olive found evidence that a duality could exist in Yang-Mills with adjoint scalars. In this scheme, the 't Hooft-Polyakov monopole forms a gauge triplet with the photon, leading to a theory equivalent to the Georgi-Glashow model but with magnetic charge replacing electric charge. The duality is believed to be realized in N=4 super-Yang-Mills. We are pursuing numerical, nonperturbative evidence for this S-duality using our lattice formulation. Two lines of approach are being taken, which I will discuss. First, we attempt to show that there is a value of the gauge coupling for which the W boson mass is equal to the monopole mass. Second, we are relating the 't Hooft loop to the Wilson loop at this self-dual coupling. On a somewhat unrelated topic, we also discuss the determination of anomalous dimensions on the lattice. In the dual gravitational picture these correspond to masses of fields in the bulk, so that some aspects of the gauge-gravity duality could be tested by such determinations. In particular in N=4 super-Yang-Mills there are predictions for the dimensions of non-protected operators at the self-dual point, based on the superconformal bootstrap.
MAR
29
Tuesday
Physics Colloquium
"Quark-Gluon Plasma: An Old and New Phase of Quantum Matter"
Presented by Jinfeng Liao, Indiana University
3:30 pm, Large Seminar Room, Bldg. 510
Tuesday, March 29, 2016, 3:30 pm
Hosted by: Robert Pisarski
The use of fire was instrumental for human civilization. Early conception of varied phases of matter as well as transitions among them, perhaps developed from e.g. burning wood and heating water. Those ancient pursuits continue into the modern quest for understanding the structure of matter under extreme conditions: what's the phase of matter when heated to unprecedented temperature? The answer to this question relies upon our understanding of the strong nuclear force, which is described by quantum chromodynamics (QCD). First principle calculations of QCD predict that the normal nuclear matter, when heated to be hot enough, will change into a new phase of matter called the quark-gluon plasma (QGP). In fact, the QGP was an old phase of matter that occupied the early universe shortly after the Big Bang. Today, such primordial droplets of QGP can be re-created repeatedly and measured precisely in relativistic heavy ion collisions (often called the Little Bangs). Remarkable discoveries have been made at the Relativistic Heavy Ion Collider (RHIC) and the Large Hadron Collider (LHC) that together reveal the QGP as a nearly perfect quantum liquid with superior opaqueness. We will discuss a number of novel properties of QGP. In particular we will highlight the recent progress on how certain unusual transport phenomena stemming from microscopic chiral anomaly, which is intrinsically quantum mechanical, could manifest themselves in the macroscopic QGP fluid. A very brief survey will be given on the theoretical developments, the experimental search in heavy ion collisions, as well as the recent exciting progress of such physics in Dirac and Weyl semimetals.