High Energy Physics Seminar

The monthly High Energy Physics seminar series at Tufts follows recent experimental theoretical developments in neutrino, collider, and other particle physics. Speakers are drawn predominantly from universities in the greater Boston area with occasional visitors from further afield.

Spring 2018

Unless otherwise noted, Spring 2018 seminars are held on Tuesdays at 3:00pm in Room 310 of the Collaborative Learning and Innovation Complex (CLIC) - 574 Boston Avenue in Medford.

February 13

Measuring reactor neutrino oscillations in the Double Chooz experiment

Ralista Sharankova, Tufts University


Double Chooz (DC) is a reactor neutrino oscillation experiment based at the Chooz nuclear power plant in Northern France. In 2011 DC was the first reactor neutrino experiment to report indication of non-zero theta_13, the last unmeasured neutrino mixing angle of the PMNS matrix. This result was confirmed in 2012 by independent experiments. Before the completion in December 2014 of the Near Detector (ND), situated ~400 m from the reactors, DC performed theta_13 measurement using data from the Far Detector (FD), sitting at ~1 km from the reactors. Over the past years DC has vastly improved its analysis techniques and its sensitivity to theta_13. The inclusion of ND data improves sensitivity even further, owing to the near iso-flux position of the two detectors, as well as identical detector design resulting in suppressed detection systematics. In its latest analysis, DC has boosted the event statistics by adopting a novel approach on the candidate selection, considering Inverse Beta Decay (IBD) events with neutrons captured on both Gadolinium (which is the preferred event sample in reactor neutrino experiments) and Hydrogen. This effectively increases the detection (fiducial) volume by more than three times and was made possible due to improved background rejection and reduced systematics. Precision and accuracy of theta_13 have a leading impact on the current explorations of neutrino CP violation and atmospheric mass ordering. Thus the redundancy of multiple theta_13 measurements is critical. In this talk the latest results of theta_13 by DC will be presented. Some of the DC analyses beyond theta_13 will also be addressed.

April 10

Searching for nu Physics with Liquid Argon Detectors

Roxanne Guenette, Harvard University


Neutrinos seem to hold the key to many great questions of physics. Understanding these elusive particles could provide the answer to why the Universe is dominated by matter, why the neutrino mass is so small and if there are any more types of neutrinos. However, studying neutrinos is not an easy task. Their weak interactions require very large detectors and the detail of their interactions is much more complex than previously assumed. Recent development in liquid argon (LAr) technology opens new opportunities to study neutrinos with unprecedented detail. After briefly reviewing the basis and the great questions of neutrino physics, I will present the principle of LAr detectors and describe how they can help us addressing some of the remaining puzzles of our field. I will also present the large-scale LAr neutrino experiment DUNE, describing the scientific potential of the project as well as the current status.

Fall 2017

Unless otherwise noted, Fall 2017 seminars are held on Tuesdays at 3:00pm in the Collaborative Learning and Innovation Complex (CLIC) - 574 Boston Avenue in Medford.

September 12

CLIC, Room 316

Building ATLAS' Inner Tracker: A silicon detector for the High Luminosity LHC era

Hannah Herde, Brandeis University


In the next decade, the Large Hadron Collider (LHC) will be upgraded into the High-Luminosity LHC (HL-LHC), delivering four-fold increase in instantaneous luminosity. The current ATLAS Inner Detector, composed of silicon- and gas-based trackers, cannot endure the harsher radiation environment, nor accommodate the challenging tracking environment of the HL-LHC. Consequently, the ATLAS Collaboration is creating the Inner Tracker, an all-silicon tracker composed of pixel and microstrip detectors, to replace the Inner Detector. This talk discusses the effort at Brookhaven National Laboratory to build base units, or "staves," for the microstrip barrel.

View Slides

October 3

CLIC, Room 114

The Pythia8 Event Generator for Particle Collisions: Status and Updates

Steve Mrenna, Fermilab


To be posted.

November 14

CLIC, Room 114

Searching for The Origin of Astrophysical Neutrinos Using a Non-Poissonian Statistical Method

Gabriel Collin, MIT


The IceCube neutrino observatory was designed to detect astrophysical neutrinos, which originate from outside of our solar system. IceCube has detected candidate astrophysical events, and measured a diffuse flux, but the source of these neutrinos so far remains unknown. Current approaches look for "hot spots" of neutrino events in the sky. It is also possible to describe a population of sources in terms of the number of observed events, forming a non-Poissonian statistical distribution. This distribution was used to show that the excess of gamma rays measured by Fermi-LAT around the galactic center was likely due to point sources rather than decaying dark matter. In this talk, I will present the application of this statistical method to the search for point sources in IceCube.

December 5

CLIC, Room 316

Exploring the High Energy Frontier with Precision Electromagnetic Calorimetry: CMS ECAL & The Search for di-Higgs Production

Toyoko Orimoto, Northeastern University


The Compact Muon Solenoid (CMS) Experiment is a general-purpose particle detector experiment at the Large Hadron Collider (LHC) at the CERN laboratory in Geneva, Switzerland. The CMS detector was designed with the goals of elucidating the origin of electroweak symmetry breaking and discovering new physics at the high energy frontier. The CMS electromagnetic calorimeter (ECAL) is a high-resolution detector made of 75k scintillating lead tungstate crystals, and its excellent energy resolution was crucial for the discovery of the Higgs boson, in particular in the diphoton and four lepton final states. During the Phase II Upgrade program, the CMS ECAL barrel electronics will be upgraded to accommodate the higher event rates and latency required at the High-Luminosity LHC (HL-LHC). A major benchmark for the CMS physics program at the HL-LHC will be the measurement of di-Higgs production, for which the final state with two photons and two b-quarks will be the most sensitive. I describe the CMS ECAL detector and the status of the Phase II Upgrade for the ECAL barrel. I will also report on the search for di-Higgs production in the two photon and two b-quark final state with Run 2 data, and the prospects for the search at the HL-LHC.