Nuclear and Particle Physics Colloquium (NPPC)


 

Mondays  |  Refreshments 3:30 PM  |  Talk: 4:00 PM  |  Kolker Room, 26-414

 

Committee: William Detmold, Chair ~ Daniel Harlow ~ Philip Harris ~ Or Hen

Colloquia Archives

Fall 2018

 

hosted by: Janet Conrad

Jie Zhao, Purdue University

Winner of the 2018 Lee Grodzins Postdoctoral Award

Search for the chiral magnetic effect in relativistic heavy-ion collisions

Abstract: Metastable domains of fluctuating topological charges can change the chirality of quarks and include local P and CP violations in quantum chromodynamics (QCD). This can lead to observable charge separation along the direction of the strong magnetic field produced in relativistic heavy-ion collisions, a phenomenon called the chiral magnetic effect (CME). An observation of the CME-induced charge separation would confirm several fundamental properties of QCD, namely, restoration of the approximate chiral symmetry, non-trivial topological structures of the QCD vacuum, and local P and CP violations. It could also explain the magnitude of the matter-antimatter asymmetry in the present universe. 

I will discuss the current status of the experimental search for the CME, especially the recent progresses in the understanding of the background issues, and new ideas to search for the CME free of background combinations.

time:    4:00 p.m.
place:   Kolker Room (26-414)

(refreshments at 3:30 p.m.)


 

hosted by: Janet Conrad

Erik Blaufuss, University of Maryland

The Search for Sources of IceCube Astrophysical Neutrinos

Abstract:The IceCube Neutrino Observatory instruments a cubic-kilometer of glacial ice under the Amundsen-Scott South Pole Station, Antarctica to detect neutrinos above ~100 GeV and perform astroparticle observations of the Universe. Astrophysical neutrinos are expected to be created in the birthplaces of high-energy cosmic rays, and point the way back to these elusive sources. Since IceCube's detection of a diffuse flux of high-energy astrophysical neutrinos in 2013, identifying their sources has been the primary science goal. This talk with will present the latest measurements of the astrophysical neutrino flux and highlight results from realtime alerts generated by astrophysical neutrino detections that trigger rapid follow-up observations by the community. In particular, a neutrino alert in September, 2017 triggered world-wide astronomical observations, and provide evidence that the Fermi-LAT identified blazar TXS 0506+056 is the first multi-messenger source producing neutrinos, as well as an accelerator of cosmic rays. Potential upgrades to IceCube will also be discussed, including the physics potential of a future IceCube-Gen2 facility at the South Pole.

time:    4:00 p.m.
place:   Kolker Room (26-414)

(refreshments at 3:30 p.m.)


 

hosted by: Or Hen

Or Hen, MIT

Neutron Star Droplets and the Quarks Within

Abstract: Neutron stars are one of the densest strongly-interacting many-body systems in our universe. A main challenge in describing the internal structure and dynamics of neutron stars steams from our current lack in understanding the short-ranged part of the nuclear interaction and its relation to the underlaying quark-gluon substructure of nuclei.

In this talk I will present new results from high-energy electron scattering experiments that probe the short-ranged part of the nuclear interaction via the hard breakup of Short-Range Correlations (SRC) nucleon pairs. As the latter reach densities comparable to those existing in the outer core of neutron stars, they represent ’neutron stars droplets’ who’s study can shed new light to the dynamical structure of neutron stars. Special emphasis will be given to the effect of SRCs to the behavior of protons in neutron-rich nuclear systems and how it can impact the cooling rates and equation of state of neutron stars. Pursuing a more fundamental understanding of such interactions, I will present new measurements of the internal quark-gluon sub-structure of nucleons and show how its modification in the nuclear medium relates to SRC pairs and short-ranged nuclear interactions.

Given time I will also discuss the development of new effective theories for describing short-ranged correlations, the way in which they relate to experimental observables, and the emerging universality of short-distance and high-momentum physics in nuclear systems.

time:    4:00 p.m.
place:   Kolker Room (26-414)

(refreshments at 3:30 p.m.)


 

hosted by: Or Hen

Thomas Aumann, IKP Technische Universität Darmstadt

Physics with Radioactive Beams

Abstract: Atomic nuclei are strongly-interacting many-body systems build from nucleons. The understanding of their properties is fundamental for many areas of physics including in particular nuclear astrophysics. The advent of large-scale facilities producing beams of "exotic" short-lived nuclei has allowed to enter new regions of the nuclear chart and to investigate properties and reactions of nuclei with extreme neutron-to-proton ratios. The experimental determination of how nuclear properties evolve as a function of their nucleonic composition allows thereby stringent tests of modern nuclear theory, and provides the basis for the understanding of astrophysical processes as the element synthesis in the universe. A prominent and challenging example is the rapid neutron-capture process occurring when two neutron stars merge, which is responsible for the production of a large fraction of the elements we find in our solar system. After an introduction into the field of physics with radioactive beams, I will discuss some selected recent experimental results obtained at R3B (Reactions with Relativistic Radioactive Beams) at GSI and the SAMURAI setup at RIKEN in Japan. The physics questions addressed are related to the properties of asymmetric nuclei and nuclear matter, and the limits of nuclear binding.

time:    4:00 p.m.
place:   Kolker Room (26-414)

(refreshments at 3:30 p.m.)


 

Columbus Day Holiday - No Talk this Week

 

hosted by: Will Detmold

Saori Pastore, Washington University in St. Louis

Neutrinos and Nuclei

Abstract: The past decade has witnessed tremendous progress in the theoretical and computational tools that produce our understanding of light nuclei. A number of microscopic calculations of nuclear structure and reactions have successfully explained the available experimental data, yielding a complex picture of the way nuclei interact with electroweak probes. In this talk, I will present recent progress in microscopic calculations of nuclear structure and reactions, with emphasis on their impact on major experiments probing fundamental symmetries and neutrino properties.

time:    4:00 p.m.
place:   Kolker Room (26-414)

(refreshments at 3:30 p.m.)


 

hosted by: Phil Harris

David R. Curtin, University of Toronto

Particle Physics at the Lifetime Frontier

Abstract:We think of particle physics as making progress when we probe smaller and smaller size scales, but sometimes new signatures can show up far away from highly energetic particle collisions. I explain why Long Lived Particles (LLPs) could be the harbingers of new physics beyond the Standard Model, and why they are motivated by some of the most fundamental mysteries in particle physics today, like the Matter-Antimatter Asymmetry of the Universe, Dark Matter, and the Hierarchy Problem. LLP signatures can be spectacular but are easily missed in standard searches, which could be the reason that we have not yet seen new physics at CERN's Large Hadron Collider. Exploring this Lifetime Frontier requires new capabilities. I will introduce the MATHUSLA proposal that aims to build a large but relatively simple detector on the surface at CERN to catch these elusive LLPs, and also discuss other detector proposals that MATHUSLA has inspired. Together, these new experiments may hold the key to discovering the missing puzzle pieces of new physics that could be hiding at the Lifetime Frontier.

time:    4:00 p.m.
place:   Kolker Room (26-414)

(refreshments at 3:30 p.m.)


 

hosted by: Daniel Harlow

Brian Swingle, University of Maryland

Studying Quantum Matter on NEar-Term Quantum Computers

Abstract:From the point of view of fundamental physics and materials science, one of the greatest promises of quantum information science is a new set of quantum computational tools for addressing previously intractable problems. However, at present we find ourselves in an age of embodied quantum information, where the substrate carrying the information cannot yet be abstracted away and effects of noise cannot be neglected. Nevertheless, I will argue that such noisy, intermediate size quantum devices may be useful for addressing open problems in quantum many-body physics, and potentially quantum field theory. Specifically, I will discuss a way to organize information in a quantum system scale by scale, a kind of renormalization group flow for states, and discuss how near term quantum computers may enable new calculations using this representation of quantum states.

time:    4:00 p.m.
place:   Kolker Room (26-414)

(refreshments at 3:30 p.m.)


 

hosted by: Kerstin Perez

Laura Newburgh, Yale University

New Probes of Old Structure: Cosmology with 21cm Intensity Mapping and the Cosmic Microwave Background

Abstract:Current cosmological measurements have left us with deep questions about our Universe: What caused the expansion of the Universe at the earliest times? How did structure form? What is Dark Energy and does it evolve with time? New experiments like CHIME, HIRAX, and ACTPol are poised to address these questions through 3-dimensional maps of structure and measurements of the polarized Cosmic Microwave Background. In this talk, I will describe how we will use 21cm intensity measurements from CHIME and HIRAX to place sensitive constraints on Dark Energy between redshifts 0.8 -- 2.5, a poorly probed era corresponding to when Dark Energy began to impact the expansion history of the Universe. I will also discuss how we will use data from new instruments on the ACT telescope to constrain cosmological parameters like the total neutrino mass and probe structure at late times.

time:    4:00 p.m.
place:   Kolker Room (26-414)

(refreshments at 3:30 p.m.


 

Veterans Day Holiday - No Talk this Week

 

hosted by: TBA

TBA

TBA

Abstract: TBA

time:    4:00 p.m.
place:   Kolker Room (26-414)

(refreshments at 3:30 p.m.)


 

hosted by: TBA

TBA

TBA

Abstract: TBA

time:    4:00 p.m.
place:   Kolker Room (26-414)

(refreshments at 3:30 p.m.)


 

hosted by: TBA

TBA

TBA

Abstract:

time:    4:00 p.m.
place:   Kolker Room (26-414)

(refreshments at 3:30 p.m.)