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Lunchtime Seminars

Tuesdays ~ 12pm ~ Kolker Room, 26-414

 

Committee:
Gunther Roland, Chair ~ William Barletta ~ Paolo Zuccon


 

February 4, 2014

hosted by:   PROF. MARKUS KLUTE


Dr. Lauren Tompkins (University of Chicago)

Just the Beginning:  the Post-Higgs Discovery LHC

Abstract:  The first run of the Large Hadron Collider was an unequivocal success. Its marquee result, the Higgs Boson discovery, revealed the keystone of the Standard Model of fundamental particle interactions. However, the particle physics community expects that the era of discovery for the LHC is just beginning. In this talk I will discuss the post-Higgs discovery landscape, explain why LHC physicists are so excited about the physics prospects of a 14 TeV LHC, and present a detector upgrade, the Atlas Fast Tracker, which will improve the ATLAS experiment's ability to record collisions which might contain new physics. In particular, I will focus on the role of heavy fermions which are critical to the understanding of the Higgs Boson and also play a prominent role in many theories of physics beyond the Standard Model.

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

(Lunch will be served.)

 


February 11, 2014

hosted by:   PROF. ROBERT REDWINE


Dr. Jin Huang (Brookhaven National Laboratory)

Exploring New Frontier of Quantum Chromodynamics with Polarized Nucleons

Abstract:  The mass of the visible universe is dominated by the mass of nucleons (protons and neutrons), which in turn stems from quantum chromodynamics fields inside nucleons. However, this fundamental structure of matter is still not fully understood. Experimentally, we can study the inner clock working of nucleons using hard scatterings, including deep inelastic lepton-nucleon scattering (DIS) and high-energy nucleon-nucleon collisions. New generation of experiments, which are sensitive to both the spin and transverse motion of quarks and gluons, reveals novel information on the nucleon structure. Among these experiments, three complementary programs will be discussed in this talk: polarized semi-inclusive DIS experiments at Jefferson Lab, recent-to-future forward upgrade of PHENIX experiment and the future electron-ion collider.

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

(Lunch will be served.)


February 18, 2014

hosted by:   PROF. GUNTHER ROLAND


Dr. Naoko Kurahashi Neilson (University of Wisconsin)

Discovery of Neutrinos from Astrophysical Sources with IceCube

Abstract:  High-energy neutrinos are thought to be emitted by astronomical objects such as active galactic nuclei, gamma-ray bursts, and supernova remnants. However, due to their small predicted flux and large backgrounds from neutrinos and muons created in the earth's atmosphere, they had not been observed until now. The IceCube Neutrino Observatory instruments a cubic kilometer of ice at the South Pole to detect neutrinos mainly above 100GeV. In a high-energy (>20TeV) data set from the first 2 years of the full detector, an excess above atmospheric backgrounds is observed. These neutrino events are also incompatible in energy spectrum and arrival direction, therefore they are the first observation of astrophysical neutrinos. Studies on the arrival direction are performed to determine the exact astronomical sources, signaling the birth of neutrino astronomy.

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

(Lunch will be served.)


February 25, 2014

hosted by:   PROF. MARKUS KLUTE


Dr. Philip Harris (CERN)

The Odd Couple:  Finding Higgs to τ τ and High Intensity Running in CMS

Abstract:  Direct confirmation of the Higgs boson's coupling to fermions has only become apparent over the last year, most predominantly with evidence that the Higgs couples to τ leptons. With large backgrounds, and small comparative signal size, resolving the Higgs decays to τ leptons requires precision physics in the messy environment of high intensity running of the LHC. At such intensities, a specific collision must be resolved on top of twenty or more additional collision occurring at the same time (known as pileup). The added difficulty of pileup has forced a rethinking of our approach to resolve fundamental physics objects, in particular jets and neutrinos (in the form of missing transverse energy, MET). To resolve the issue of high pileup in jets and MET, a new technique relying on elements of jet substructure has been implemented. This work, along with the larger field of jet substructure, is quickly opening the door to a plethora of new physics at the LHC. In this talk, I present the CMS Higgs to τ τ evidence, with emphasis on new approaches developed to mitigate the effects of pileup. Finally, I show how such an approach against pileup is changing the future design of detectors at the energy frontier.

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

(Lunch will be served.)


March 4, 2014

hosted by:   PROF. ROBERT REDWINE


Dr. Rhiannon Meharchand (Los Alamos National Laboratory)

Nuclear Data Measurements at LANSCE:  The NIFFTE Fission TPC

Abstract:  The Neutron and Nuclear Science Group at Los Alamos National Laboratory (LANSCE-NS) has a diverse experimental program aimed at measuring nuclear data: prompt fission neutron and gamma output; fission fragment mass, charge, and energy distributions; cross sections for direct and surrogate (n,γ), (n,2n), (n,X), and (n,f) reactions. These data are fundamental to nuclear energy and defense applications, which are increasingly dependent upon advanced simulation and modeling due to testing restrictions and high development costs.

With respect to neutron-induced fission cross section measurements, sensitivity studies have indicated a need for high-precision data, as uncertainties in nuclear data inputs propagate into uncertainties in key performance parameters for applications. To address this need, the Neutron Induced Fission Fragment Tracking Experiment collaboration has developed a fission Time Projection Chamber (TPC). Designed to address sources of systematic uncertainty that have plagued previous measurements, the fission TPC is based on well-established technology, miniaturized and modified for use in fission research.

Fission TPC experiments take place at the Los Alamos Neutron Science Center (LANSCE) Weapons Neutron Research facility, a spallation neutron source which provides a white neutron spectrum ranging from hundreds of keV to hundreds of MeV. During the 2012 LANSCE run cycle, the fission TPC was used to measure the 238U/ 235U (n,f) cross-section ratio. This ratio will be used to benchmark TPC performance.

An overview of the LANSCE-NS experimental pro-gram and the fission TPC project will be presented along with early performance results.

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

(Lunch will be served.)


March 11, 2014



Dr. Penny Slocum (Yale)

New Experimental Constraints in Searches for a Light Neutral Boson at 0.1 meV

Abstract:  Several extensions to the Standard Model of elementary particles allow for light neutral particles that couple infrequently to microwave photons. The feeble interactions between these candidates and Standard Model particles qualify them in part to be the dark matter in the universe. We present results from two ongoing searches at 34 GHz with the Yale Microwave Cavity Experiment. The apparatus has two main running configurations: A two-cavity arrangement that is driven as in the "light-shining-through-walls" experiments, and a standalone TM020 cavity that runs in a listening mode. The experiment sits inside the bore of a 7 T cryomagnet oriented axially. The signal cavity is held at a temperature of 4 K and is coupled to a low noise cryogenic amplifier plus room temperature receiver. We exclude mixing between 0.1 meV photons and paraphotons at a sensitivity of \chi > 2x10^{-7}. We will also be sensitive to 0.1 meV photons from couplings between two photons and axion-like particles for g > 10^{-10}/GeV. We demonstrate the sensitivity of the experiment and discuss the implications of the measurement.

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

(Lunch will be served.)


March 18, 2014



Prof. Reina Maruyama (Yale)

Updates and Status of DM-Ice

Abstract:  Astrophysical observations and cosmological data give overwhelming evidence that the majority of the mass of the Universe is comprised of dark matter. I will describe the current status of the direct searches for dark matter. In particular, I will describe DM-Ice, a proposed direct detection dark matter experiment at the South Pole. The aim of the experiment is to directly test DAMA collaboration's assertion that they have observed the predicted annual modulation signature of dark matter. I will describe the data from the 17-kg detector which was installed in the Antarctic ice at the South Pole in December 2010 and still taking data. I will then discuss plans for the full-scale experiment.

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

(Lunch will be served.)


March 25, 2014

week of SPRING BREAK – No Lunchtime Seminar


March 31, 2013

week of OPEN HOUSE – No Lunchtime Seminar


April 8, 2014
LUNCHTIME SOCIAL



Prof. Gunther Roland (MIT)

Better Living with edX

Abstract:  With support from the MIT Office of Digital Learning, the LNS heavy-ion group is currently developing an online "School of Heavy Ion Physics", based on the edX platform. I will describe the motivation and basic concept for this effort, which may prove a useful model for other areas, and lead a discussion with the graduate students and postdocs in the audience looking for comments, suggestions and brilliant ideas.

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

(Lunch will be served.)


April 15, 2014


Dr. Kerstin Perez (Columbia University)

Antideuteron Signatures of Dark Matter with the GAPS Experiment

Abstract:  The question of the origin of dark matter, the mysterious matter known to permeate the universe, is one of the towering problems of 21st-century physics. Dozens of dark matter search experiments are currently planned or ongoing, but these efforts have been hampered by the large background rates from conventional astrophysical processes and the vast array of signatures that could indicate a dark matter interaction. The General Antiparticle Spectrometer (GAPS) experiment aims to advance these searches by detecting low-energy antideuterons that result from the self-annihilation of dark matter particles in the Galactic halo, providing an essentially background-free signature of dark matter. This signal probes supersymmetry, extra-dimensional theories, and other modes dark matter production, complementing and extending the reach of current experiments. In this seminar, I will present the design and discovery potential of the baloon-borne GAPS experiment, especially in the context of recent dark matter results.

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

(Lunch will be served.)


April 22, 2014



Prof. Markus Klute (MIT)

Status, Prospects, and Interplay with Searches for BSM of Higgs Boson Coupling Measurements

Abstract:  The discovery of a Higgs boson by the LHC experiments opened new possibilities to explore electroweak symmetry breaking and potentially a window into beyond- Standard Model physics such as an extended Higgs sector, anomalous Higgs boson production mechanisms, or rare Higgs boson decay modes. Such discoveries would represent a smoking gun for an extended Higgs sector, and could have long-reaching implications on our understanding on how nature works at its most fundamental level. In this talk I will cover the status, prospects and the interplay of Higgs boson coupling measurements with searches for a BSM Higgs sector.

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

(Lunch will be served.)


April 29, 2014



Dr. Jan C. Bernauer (MIT)

Proton Form Factors:  Interesting at All Scales

Abstract:  In recent years, the interest in the proton form factors has surged. In the talk, I will showcase recent results as well as current and upcoming experiments with a focus on OLYMPUS as a Two-Photon-Exchange measurement ("high Q2"), the Mainz form factor measurement at mid to low Q2, and the proton radius puzzle which is a unique connection between nuclear and atomic physics.

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

(Lunch will be served.)


May 6, 2014



Dr. Jonathon Asaadi (Syracuse University)

The MicroBooNE and ArgoNeuT Experiments and the Future of Liquid Argon Time Projection Chambers

Abstract:  Liquid argon time projection chambers (LArTPC's) provide an extraordinary level of information about the interactions of neutrinos. Amongst the several different efforts ongoing at Fermi National Accelerator Laboratory to develop the liquid argon detector technology and utilize it to study neutrino interactions are the MicroBooNE and ArgoNeuT experiments. The MicroBooNE experiment is a 170 ton total mass LArTPC. MicroBooNE will be deployed in the Booster neutrino beam at Fermilab and is scheduled to start taking data in early 2014. The ArgoNeuT experiment deployed a relatively small 0.7 ton total mass LArTPC in the NuMI neutrino beamline at Fermilab, running from September 2009 to February 2010. The data collected is now being analyzed and used to measure neutrino interaction cross-sections. This talk will present an overview of LArTPC's, the current status of the assembly, installation, and operational readiness of the MicroBooNE detector, ongoing data analysis from ArgoNeuT data, and an overview of future LArTPC's experiments currently proposed.

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

(Lunch will be served.)


May 13, 2014



Prof. Mark Strikman (Penn State University)

Revealing Nucleon and Nucleus Flickering in pA Collisions at the LHC

Abstract:  Increase with energy of the coherence length in scattering of protons leads to a semi-classical picture of interaction where nucleon interacts in frozen configurations of different interaction strength. Information about variance of the distribution over the interaction strengths directly measured in forward diffractive pN scattering is reviewed. Evidence for presence of significant fluctuations of the gluon density in nucleon is presented. We evaluate the number of wounded nucleons in soft and hard pA processes, the multiplicity of jets in the proton fragmentation region as a function of the fluctuation of interaction strength for RHIC and LHC energies. We argue that parton configurations containing a parton carrying the x≥0.5 fraction of the proton momentum interact significantly weaker than on average leading to a change of the pattern of the dependence of the jet multiplicity on the number of the wounded nucleons. This expectation is consistent with preliminary data of CMS and ATLAS. We also study leading twist shadowing and the EMC effect for superdense nuclear matter configurations probed in the events with larger than average number of wounded nucleons.

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

(Lunch will be served.)