Lunchtime Seminars


 

Tuesdays  |  12:00 PM  |  Kolker Room, 26-414

 

Committee: Gunther Roland, Chair ~ Douglas Hasell

 


Adi Ashkenazi, MIT

Probing ν Interactions for ν Physics

Abstract: The ability of current and next generation accelerator based neutrino oscillation measurements to reach their desired sensitivity requires a high-level of understanding of neutrino-nucleus interactions. These include precise estimation of the relevant cross sections and the reconstruction of the incident neutrino energy from the measured final state particles. Neutrino energies are inferred from the charged particles produced following their interactions with atomic nuclei. Incomplete understanding of these interactions can skew the reconstructed neutrino spectrum and thereby bias the extraction of fundamental oscillation parameters and searches for new physics. In this talk I will present results for the MicroBooNE experiment of the first exclusive differential cross section measurement using neutrino-Argon Quasi Elastic like interactions. In addition, using wide phase-space electron scattering data, collected using the CLAS spectrometer at the Thomas Jefferson National Accelerator Facility (JLab), the reconstruction of the incoming lepton energy from the measured final state is being tested. Disagreements with current event generators, used in the analysis of neutrino oscillation measurements, are observed which indicate underestimation of nuclear effects. The impact of these findings on bias in oscillation analyses will be discussed.

time:    Noon
place:   Kolker Room (26-414)


(Lunch will be served at 11:50)


 

 


Presidents' Day adjusted schedule- No Talk This Week


 



Yi Chen, MIT

Probing the Quark-Gluon Plasma with Jet Substructure in Heavy Ion Collisions

Abstract: During ultra-relativistic heavy ion collisions, a dense QCD matter is formed. This colored, hot, and dense quark-gluon plasma (QGP) interacts and modifies the evolution of hard partons which later manifest themselves into jets in experiments. The loss of energy by jets, known as jet quenching, is an excellent phenomenon we can use to probe the properties of QGP. As jets are large and composite objects, there is a lot of information available: not only in the total energy loss but also in the modification of large scale structures inside the jet. At the LHC, the experiments have successfully collected a large amount of PbPb and pPb collision data which allows us to study the QGP in greater detail than before. Recent measurements on jet measurements using substructure techniques will be discussed.

time:    Noon
place:   Kolker Room (26-414)


(Lunch will be served at 11:50 a.m.)


 



Yen-Jie Lee, MIT

Physics Plan for Quark-Gluon Plasma Analyses in LHC Run 3 and 4

Abstract: Studies of future physics opportunities for high-density QCD with ions and proton beams at LHC have been carried out by theorists and LHC experiments. Those studies, included of the CERN yellow report of HL/HE LHC physics, are inputs to the European Strategy for Particle Physics. This talk summarizes the current status of the QGP analyses, current understanding, open questions and the physics plan described in the yellow report.

time:    Noon
place:   Kolker Room (26-414)


(Lunch will be served at 11:50 a.m.)


 



Kenneth Hicks, Ohio University

A Sampling of Results on Hadron Spectroscopy from CLAS

Abstract: The CLAS detector, a Large Acceptance Spectrometer, can detect many multi-particle final states, similar to many high-energy detectors. A few-GeV photon beam, made from the CEBAF electron beam at Jefferson Lab, incident on targets of hydrogen and deuterium has produced a wealth of data that allows us to study the spectrum of states of the nucleon, called N* states. In addition, the same data set can be used to study the spectrum of excited mesons that decay to pions and kaons. In this talk, I will describe four papers that the Ohio group has published recently that impact hadron spectroscopy. Future directions for analysis using the new clas12 detector will be explored.

time:    Noon
place:   Kolker Room (26-414)


(Lunch will be served at 11:50 a.m.)


 



Kyungseon Joo, University of Connecticut

Studies of 3-D Structure of the Nucleon from CLAS and CLAS12 at Jefferson Lab

Abstract: Recent developments of generalized parton distributions (GPDs) and transversely dependent momentum distributions (TMDs) have opened a new window on a 3-D imaging of the nucleon, going far beyond the one-dimensional, longitudinal structure probed in deep-inelastic scattering, and the transverse structure encoded in the different form factors. The 3-D imaging of the valence quarks is a cornerstone of the new 12 GeV experimental program at Jefferson Lab, and a future proposed US-based electron ion collider (EIC) will extend this imaging to sea quarks and gluons. In this talk, I will describe recent measurements in exclusive and semi-inclusive deep processes with the CLAS detector, a Large Acceptance Spectrometer at Jefferson Lab to study 3-D structure of the nucleon, and I will also explore future directions using the new CLAS12 detector.

time:    Noon
place:   Kolker Room (26-414)


(Lunch will be served at 11:50 a.m.)


 



Spring Break- No Talk This Week


 



Carlos Argüelles-Delgado, MIT

Latest Results from IceCube on High-Energy Astrophysical Neutrinos and Related Beyond Standard Model Searches

Abstract: The IceCube neutrino observatory has established the existence of an astrophysical diffuse high-energy neutrino component. This discovery was made using the high-energy starting event sample, which uses a veto to significantly reduce atmospheric background. In this talk I will present the latest astrophysical neutrino flux measurement using high-energy starting events. This latest iteration of the analysis updates the event properties with the newer glacier ice models and has an improved systematic treatment. Using this sample I will report on the first search for anomalous space time effects using astrophysical neutrino flavour data in IceCube. Introducing new effective operators can drive non-standard neutrino flavour mixing, modifying the flavour ratios compared to standard cases. We found no evidence of such flavour anomalies. However, we demonstrate the sensitivity of this new approach goes far beyond any known techniques. Importantly, we achieve the necessary precision to probe new physics using neutrino flavour expected by Planck scale theories. Our quest continues.

time:    Noon
place:   Kolker Room (26-414)


(Lunch will be served at 11:50 a.m.)


 



Jay Hyun Jo, Yale University

COSINE-100 NaI(Tl) Dark Matter Experiment: Testing DAMA's Claim for a Dark Matter Discovery

Abstract: Astrophysical observations give overwhelming evidence for the existence of dark matter, yet we do not know what it is. For over 20 years, the DAMA collaboration has asserted that they observe a dark matter-induced annual modulation signal but their observation has yet to be confirmed. COSINE-100 is a joint experiment between DM-Ice and KIMS collaboration to test DAMA's claim, situated at the Yangyang Underground Laboratory in South Korea. COSINE-100 consists of eight low background NaI(Tl) crystals with a total mass of 106 kg and 2000 liters of liquid scintillator as an active veto, and the physics run of the experiment began in September 2016. The current results from COSINE-100, including the status of the field, will be presented.

time:    Noon
place:   Kolker Room (26-414)


(Lunch will be served at 11:50 a.m.


 



Patriots Day adjusted schedule - No Talk This Week


 



Ross Corliss, MIT

sPHENIX: Status and Goals of RHIC's Next Detector

Abstract: Experiments at the Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Lab have used heavy ion collisions to study the Quark Gluon Plasma for nearly two decades. The sPHENIX experiment will continue this work, using a new suite of detectors to take advantage of the increased luminosity that accelerator upgrades have made possible.

The sPHENIX detector will use hadronic and electromagnetic calorimeters along with precision tracking detectors to make a variety of measurements that, combined with those from LHC experiments, will allow us to probe the temperature dependence of QGP properties. I will introduce some of these measurements, and discuss the design and status of the sPHENIX project itself, with an emphasis on MIT's role in the inner tracking.

time:    Noon
place:   Kolker Room (26-414)


(Lunch will be served at 11:50 a.m.)


 



Ivica Friščić, MIT

A New Approach to Determine The Radiative Capture Reaction Rate of 12C(α,γ)16O at Astrophysical Energies

Abstract: For over five decades a principal goal of experimental nuclear astrophysics has been to improve the accuracy of the 12C(α,γ)16O reaction rate at stellar energies. Due to rapid fall of the cross section below 2 MeV, the existing measurements of the direct reaction are dominated by an increasing statistical uncertainty, which results in uncertainty greater than 100% for the data below 1 MeV.

Here, we have focused on the energy region between 0.7 and 1.7 MeV, performed a calculation of the 16O(e,e’α)12C reaction rate assuming high luminosity from state-of-the-art gas targets and a new generation of energy-recovery linear (ERL) electron accelerators under development, and showed that it can be used to significantly improve the statistical uncertainties of the 12C(α, γ)16O reaction rate in terms of astrophysical S-factors E1 and E2. This, in turn, is a critical step to increase the precision of the extrapolation of the S-factors to stellar energies, which are the essential input for any nucleosynthesis and stellar evolution models.

time:    Noon
place:   Kolker Room (26-414)


(Lunch will be served at 11:50 a.m.)


 



Camelia Mironov, MIT

The Quark Gluon Plasma: Where Is It, and Where Are We in Understanding It?

Abstract: After more than 30 years, the study of quark gluon plasma (QGP), the high-temperature and large-density matter made of deconfined quark and gluons, has reached a critical point. The extreme state-of-matter thought to be found in neutron stars or (for very short times) in the aftermath of relativistic heavy-ion collisions, seems to have been created also in smaller systems (like proton-proton and proton-ion collisions).

The talk will show some of the latest experimental findings related to the presence of QGP in small systems. The results use mainly data collected by the LHC experiments during Run 2, between 2015 and 2018.

time:    Noon
place:   Kolker Room (26-414)


(Lunch will be served at 11:50 a.m.)


 



Jackson Pybus, MIT

First Constraints on the Nuclear Force at Neutron Star Densities

Abstract: The strong nuclear interaction between nucleons (protons and neutrons) is the effective force that holds the atomic nucleus together. This force stems from fundamental interactions between quarks and gluons that are governed by QCD but cannot be calculated directly. Therefore, nuclear interactions are described using parametrized effective models. While model parameters governing the interaction at typical internucleon distances in nuclei are well constrained, the shorter distance parameters are not. This limits the predictive power of current models for describing high-density nuclear matter such as in the cores of neutron stars.

In this talk I present results from new high-energy electron scattering measurements that isolate nucleon pairs in short-distance, high-momentum, configurations that constrain nucleon-nucleon (NN) interactions at previously unreachable short distances.

time:    Noon
place:   Kolker Room (26-414)


(Lunch will be served at 11:50 a.m.)