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Lunchtime Seminars

Tuesdays ~ 12pm ~ Kolker Room, 26-414

 

Committee:
Gunther Roland, Chair ~ Doug Hasell~



February 6, 2018

Talk will begin at 1p.m. in the Kolker Room

 

Marek Karliner, Tel Aviv University

The Social Life of Heavy Quarks

I will discuss recent developments regarding new types of hadrons
involving heavy quarks: hadronic molecules, doubly heavy baryons, stable
tetraquarks and others. I will also explain how the discovery of the
doubly heavy baryon leads to quark-level analogue of nuclear fusion,
with energy release per reaction an order of magnitude greater than in
ordinary fusion.

 

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

(Lunch will be served at 11:50.)



February 13, 2018

 

Valentina Lozza, LIP Lisboa

Cosmogenic activation studies for the SNO+ experiment

 

SNO+ is a large liquid scintillator based experiment that re-uses the Sudbury Neutrino Observatory detector. The detector, located 2 km underground in a mine near Sudbury, Canada, consists of a 12 m diameter acrylic vessel, viewed by about 9300 PMTs, which will be filled with 780 tonnes of liquid scintillator.

The main physics goal of SNO+ is to search for the neutrinoless double-beta (0n2b) decay of 130Te. During the double-beta phase, the liquid scintillator will be loaded with 0.5% natural tellurium (nearly 1300 kg of 130Te). In 5 years of data taking, SNO+ expects to reach a sensitivity on the effective Majorana neutrino mass just above the inverted neutrino mass hierarchy region.

Designed as a general purpose neutrino experiment, SNO+ can additionally measure the reactor antineutrino oscillations, geo-neutrinos in a geologically-interesting location, watch for supernova neutrinos and measure low-energy solar neutrinos.

A possible source of background for experiments searching for rare events, such as neutrinoless double-beta decay, are the high Q-value, long-lived isotopes, produced by the activation of the target material through spallation reactions induced by nucleons (neutrons and protons) produced in cosmic ray showers in the atmosphere. Therefore, a study of the cosmogenic-induced isotopes in tellurium has been done, in order to define the maximum allowed exposure to cosmic rays on surface, the necessary purification factors, and the cooling down time underground.

In this talk I will present the current status and the broad physics program of SNO+, along with the studied performed on the cosmogenic activation of tellurium.


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

(Lunch will be served at 11:50.)

 


 


February 20, 2018

 

Presidents Day Holiday

 



February 27, 2018

 

James Napolitano, Temple University

New Physics with Reactor Neutrinos: Daya Bay and PROSPECT

 

Nuclear Reactors are powerful sources of electron anti-neutrinos. Experiments in the past decade have given us a wealth of new information, especially when combined with muon neutrino beams from accelerators. The neutrino mixing angles are well measured, as are the mass splittings, and we are on the verge of determining the mass hierarchy and the CP-violating phase angle. However, some mysteries remain, especially the Reactor Neutrino Anomaly and the potential for additional generations of "sterile" neutrinos. 

We will discuss what we know (and don't know) about the neutrino landscape, and how reactor neutrinos have played an important role. I will focus on the Daya Bay Reactor Neutrino Experiment, which has been running now for six years at a large scale nuclear power plant; and the Precision Oscillation and SPECTrum (PROSPECT) experiment which is about to begin taking data at a research reactor with an enriched 235U core.

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

(Lunch will be served at 11:50.)



March 6, 2018

 

Michael Ramsey-Musolf, UMass Amherst

TeV Scale Lepton Number Violation: Neutrinoless Double Beta Decay & the LHC

Determining the origin of neutrino masses remains a compelling challenge at the interface of nuclear and high energy physics. The standard see-saw neutrino mass mechanism postulates the existence of new lepton number violating (LNV) interactions at very high energy scales. In this talk, I consider the possibility that LNV interactions responsible for neutrino mass may exist at the TeV scale. I discuss how the interplay of searches for neutrinoless double beta decay and LHC searches for LNV processes may probe this possibility. I also discuss several theoretical issues pertaining to these searches for TeV scale LNV.

 

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

(Lunch will be served at 11:50.)



March 13, 2018

CANCELLED DUE TO WEATHER

Siddharth Narayanan, MIT

Identifying top quarks in the pursuit of invisible particles

Experiments at the Large Hadron Collider at CERN search for new physics at the energy frontier by attempting to produce and detect (directly or indirectly) particles beyond the Standard Model. These searches cover a broad range of final states, corresponding to a similarly broad range of new physics models. Many interesting models (including WIMP dark matter) motivate final states containing particles that are invisible to our detectors. In this talk, I will discuss the search for invisible particles produced in association with a top quark using the Compact Muon Solenoid at the LHC. Along the way, I will take a detour to describe the identification of hadronically-decaying top quarks using jet substructure and flavor-tagging. 

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

(Lunch will be served at 11:50.)



March 20, 2018

 

Alexandra Gade, Michigan State University

Exotic atomic nuclei: Probing many-body physics and the origin of the elements 

One goal of nuclear physics is a comprehensive understanding of the properties of nuclei from the interactions of the constituent protons and neutrons. This is of critical importance to address two fundamental challenges: Which combinations of protons and neutrons exist as bound systems and how are the elements synthesized in stars and their explosions? This quest for a reliable model of the atomic nucleus is at the brink of a revolution. The limits of nuclear existence can be mapped progressively with measurements of high sensitivity afforded by advances in accelerator and detector technology. An ever increasing range of short-lived nuclei (rare isotopes) becomes available for experiments that isolate specific features of the nuclear many-body problem. This presentation will show how experiments today measure complementary observables that advance our understanding of nuclear science and what enormous opportunities will be opened up once the Facility for Rare Isotope Beams (FRIB) comes online at Michigan State University.

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

(Lunch will be served at 11:50.)



March 27, 2018

 

Spring Break- No Seminar Held



April 3, 2018

 

Yang-Ting Chien, MIT

Probing heavy ion collisions using quark and gluon jet substructure

Jets are produced abundantly in high energy particle collisions, and they encode rich information about collision events across the entire range of distance scales. On the other hand, a new state of matter called the quark-gluon plasma (QGP) is believed to be produced in heavy ion collisions, and its precise properties are under active investigation using various experimental probes. In this talk, I will discuss the use of quark and gluon jets as independent probes of heavy ion collisions, and how jet substructures can provide a web to capture characteristic imprints of QGP. I will make connections between heavy ion jet modification studies and quark/gluon jet classifications, and show how jet substructure techniques can play an important role in providing consistent and comprehensive picture of jet modification, a step toward understanding the inner-working of QGP.

 

 

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

(Lunch will be served at 11:50.)


April 10, 2018

 

Alexander Leder, MIT

Rare-Event Searches with Bolometers

Rare-event searches have played an integral part in exploring new physics beyond the Standard Model, offering us the chance to bridge the disparity between our current understanding and observed phenomena such as dark matter or neutrino masses. Over the past years, these experiments have grown larger and more sophisticated, allowing us to probe new and exciting theories of the universe. At the same time, we have started to apply the technologies and techniques used in rare-event searches to more areas of applied physics, for example measuring Coherent Elastic Neutrino Nucleon Scattering (CENNS) from reactor neutrinos with Ricochet.


In this talk, I will discuss the hardware and analysis techniques required to design, construct, and extract results from these low background, rare-event searches. In particular, I will discuss the hardware and analysis related to the Cryogenic Dark Matter Search experiments and CENNS detection with Ricochet. In addition, I will discuss the measurement of the effective nuclear quenching factor via shape analysis of the highly forbidden ln-115 beta spectrum.


The measurement of the effective quenching factor in heavy nuclei has far-reaching consequences for all neutrinoless double-beta experiments independent of isotope.

 

 

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

(Lunch will be served at 11:50.)


 

April 17, 2018

 

Siddharth Narayanan, MIT

Identifying top quarks in the pursuit of invisible particles

Experiments at the Large Hadron Collider at CERN search for new physics at the energy frontier by attempting to produce and detect (directly or indirectly) particles beyond the Standard Model. These searches cover a broad range of final states, corresponding to a similarly broad range of new physics models. Many interesting models (including WIMP dark matter) motivate final states containing particles that are invisible to our detectors. In this talk, I will discuss the search for invisible particles produced in association with a top quark using the Compact Muon Solenoid at the LHC. Along the way, I will take a detour to describe the identification of hadronically-decaying top quarks using jet substructure and flavor-tagging. 

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

(Lunch will be served at 11:50.)


April 24, 2018

 

Diana Parno, Carnegie Mellon University

How to Measure CEvNS at the Spallation Neutron Source

In Summer 2017, the COHERENT collaboration announced the first observation of coherent elastic neutrino-nucleus scattering (CEvNS), a predicted Standard-Model process that had remained experimentally elusive for 44 years. This achievement built on advances in detector technology, driven by the WIMP community, and on a uniquely suited source of neutrinos. I will describe some of the technical aspects of the discovery, and show a few of the challenges and opportunities that lie ahead.

 

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

(Lunch will be served at 11:50.)


May 1, 2018

 

Mariarosaria d'Alfonso, MIT

Where are the other Higgs bosons?

The observation of a Higgs boson of a mass of approximately 125 GeV initiated a new field of study at the CERN LHC to explore its properties and to shed light on its role in the Standard Model (SM).

The detection of a charged Higgs boson would unequivocally point to new physics beyond the SM.

I will describe searches for charged Higgs bosons decaying to top and bottom in the leptonic and fully hadronic final state with the CMS experiment at LHC.

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

(Lunch will be served at 11:50.)

 



May 8, 2018

 

Yen-Jie Lee, MIT

Long-range angular correlations of charged particles in high multiplicity e+e- collisions using archived data from the ALEPH detector at LEP

First results on two-particle angular correlations for charged particles emitted in e+e− collisions using data collected at 91 GeV with the ALEPH detector at LEP are presented. With the archived data, the correlation functions are studied over a broad range of pseudorapidity η and azimuthal angle ϕ with respect to the electron-positron beam axis and the event thrust axis. Short-range correlations in small Δη which are studied with e+e− annihilations which reveal the jet-like correlations. Long-range azimuthal angle correlation functions of charged particles are studied differentially as a function of charged particle multiplicity. Those results are compared to event generators and are complementary to the studies of the long-range correlation signals in high multiplicity pp, pA and AA collisions at the RHIC and the LHC.

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

(Lunch will be served at 11:50.)

 



May 15, 2018


NO TALK THIS WEEK

 



May 22, 2018


Javier Virto, MIT

Flavor anomalies: where are we? 

Evidence for physics beyond the standard model in certain B-meson decays has been piling up in the last 5 years , through measurements of many different modes and observables. While the significance of the deviations on each single observable is not by itself large enough or unambiguous, this is arguably the largest set of coherent deviations since the establishment of the Standard Model. I will explain how we got here, where we are now, and what can we expect in the future.

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

(Lunch will be served at 11:50.)


May 29, 2018


Special LNS presentation of the NASA documentary:

AMS: The Fight for Flight

NASA has produced a documentary about the Alpha Magnetic Spectrometer (AMS), a particle physics experiment on the International Space Station. The film covers the history of this revolutionary experiment and the man behind it. Originally proposed in 1994 by Samuel Ting, a Nobel laureate and MIT Professor of Physics, and built by over 600 physicists and engineers all over the world, the Alpha Magnetic Spectrometer is by far the most complex physics experiment ever launched into space. The goal of the instrument is to help researchers unlock the mysteries of antimatter and better understand the structure of our universe. While still under construction, the AMS experiment suffered a major setback because of the Space Shuttle Columbia tragedy in 2003. Soon after, the decision was made to cancel the space shuttle program, and as a result the AMS was removed from the manifest. After ten years and $1.5B spent, there would be no ride to the space station. This film tracks the AMS's 23 year journey from the drawing table to its final home on the space station. Along the way, we look back at the adversity that principal investigator Sam Ting was forced to overcome with the help of NASA and key members of Congress. Ultimately, it's a story of one man's remarkable tenacity and that of different branches of government working with researchers in order to produce great science for the benefit of all humankind.

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

(Lunch will be served at 11:50.)