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.
Fall 2025
Unless otherwise noted, Fall 2025 seminars are held in the Collaborative Learning and Innovation Complex (CLIC) - 574 Boston Avenue in Medford.
September 25, 2025
Thursday, September 25, 1:30pm
Room 310
Speaker: Lars Bathe-Peters (University of Oxford)
Title: 2p-2h Cross-Section Systematics in DUNE
Abstract: For the operation of precision neutrino experiments, the understanding of neutrino interactions with matter is a preconditioned requirement for all detections and measurements of neutrinos. The largest uncertainties in estimating neutrino-nucleus interaction cross sections arise from the incomplete understanding of neutrino-nucleus interactions. In the study of neutrino oscillations and nuclear scattering processes, obtaining an interaction model with associated uncertainties is of substantial interest for the neutrino physics community. This talk presents studies of simulated CC 2p-2h interactions, in which a neutrino interacts with a bound pair of nucleons. This interaction mode is very poorly constrained by current data. A comparison of three leading CC 2p-2h models is presented, along with a number of uncertainty parameters that have been implemented to account for model-to-model discrepancies in the DUNE oscillation analysis.
October 9, 2025
Thursday, October 9, 2:00pm
Room 206
Speaker: Richard Ruiz, Associate professor at the Institute of Nuclear Physics in Krakow, Poland.
Title: Vector Boson Scattering: Status and Prospects for the Large Hadron Collider and Beyond
Abstract: The scattering of electroweak bosons at TeV-scale super colliders is a powerful mechanism that probes spin and charge configurations inaccessible to quark and gluon scattering. Electroweak vector boson scattering (VBS) processes give unique insights into the Standard Model's gauge and Higgs sectors, as well as into models of new physics. In this talk, we review experimental results and ongoing theoretical developments of VBS at the Large Hadron Collider, its high luminosity upgrade, and its potential successors. Prospects for measuring the weak boson content of the proton is also discussed.
Spring 2025
Unless otherwise noted, Spring 2025 seminars are held in the Collaborative Learning and Innovation Complex (CLIC) - 574 Boston Avenue in Medford.
Wednesday, March 26, 2025
2:30pm
574 Boston Ave., Room 402
Speaker: Rik Gran, University of Minnesota Duluth
Title: Measuring the nucleon axial form factor in deuterium and hydrogen can’t be that hard?
Abstract:
In a recent paper in Nature, the MINERvA neutrino cross section experiment presented a measurement of the axial form factor of the nucleon using anti-neutrino reactions on protons (hydrogen nuclei). This is the first new nucleon data since the 1980’s bubble chamber measurements that used neutrino + neutron (in deuterium) reactions. Phenomenological nucleon form factors are essential information for two customers. They are used in the calculation of the baseline event rates for neutrino + nucleus interactions used in the search of other phenomena, such as neutrino oscillation parameters and CP violation. They can also be calculated using QCD lattice techniques, where calculations may in principle be more precise than the existing measurements. This talk will split between celebrating the 50 year history of the deuterium measurements and describing the new MINERvA measurement, with implications for current and upcoming neutrino experiments such as T2K, NOvA, SBN, and DUNE.
Tuesday, February 18, 2025
10:30am
574 Boston Ave., Room 310
Speaker: Julía Tena Vidal, Tel Aviv University
Title: Unravelling hadron formation through lepton-nucleus scattering
Abstract: Hadronization is a quantum chromodynamics (QCD) process in which high-energy quarks evolve into colourless hadrons. Its time evolution in the nucleus, driven by non-perturbative QCD, is still not well understood. Hadronization is influenced by finite timescales and the nuclear environment, directly affecting the observed hadron yields and kinematics in experiments. The precise study of hadronization is a cornerstone of the scientific mission of the future Electron-Ion Collider (EIC) experiment. It is also critical for neutrino experiments in the few-to-100 GeV range, such as the Deep Underground Neutrino Experiment (DUNE), where pion production processes dominate. These depend on precise hadron production models for neutrino energy reconstruction, which is essential for neutrino oscillation studies and searches for physics beyond the Standard Model. Hadron production is studied in electron-scattering experiments, which benefit from high statistics and well-known monochromatic beams. The CLAS large-acceptance spectrometers provide with new exclusive hadron-production data to uncover the properties of hadron production by using 1–11 GeV electron beams with various nuclear targets of interest for DUNE. This seminar presents a new pion production measurement with CLAS data and a novel initiative to develop the first data-driven hadronization model tailored for and experiments at the few to 100 GeV energy range. By integrating three interconnected efforts— improved lepton-scattering simulations, new hadron-production and measurements, and the tuning of lepton-nucleus event generators—this work aims to advance our understanding of hadron formation and hadronization in the nuclear medium and reduce systematic uncertainties in experiments.
-
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, 2018
Measuring reactor neutrino oscillations in the Double Chooz experiment
Ralista Sharankova, Tufts University
Abstract:
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, 2018
Searching for nu Physics with Liquid Argon Detectors
Roxanne Guenette, Harvard University
Abstract:
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.
-
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, 2017
CLIC, Room 316
Building ATLAS' Inner Tracker: A silicon detector for the High Luminosity LHC era
Hannah Herde, Brandeis University
Abstract:
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.
October 3, 2017
CLIC, Room 114
The Pythia8 Event Generator for Particle Collisions: Status and Updates
Steve Mrenna, Fermilab
Abstract:
To be posted.
November 14, 2017
CLIC, Room 114
Searching for The Origin of Astrophysical Neutrinos Using a Non-Poissonian Statistical Method
Gabriel Collin, MIT
Abstract:
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, 2017
CLIC, Room 316
Exploring the High Energy Frontier with Precision Electromagnetic Calorimetry: CMS ECAL & The Search for di-Higgs Production
Toyoko Orimoto, Northeastern University
Abstract:
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.
-
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.
Unless otherwise noted, all seminars are held at Collaborative Learning and Innovation Complex (CLIC) - 574 Boston Avenue in Medford.
Wednesday, February 15, 2017 | 10:30am, Room 310
Inclusive and Semi-inclusive Neutrino Reactions with Nuclei
T. William Donnelly, MITAbstract: Theoretical issues involved in studies of inclusive charge-changing neutrino reactions with nuclei and their extensions to semi-inclusive processes will be discussed. For the former, the basic SuperScaling Approach (SuSA) will be summarized and scaling violations from meson-exchange current contributions quantified in terms of the so-called SuSAv2+MEC model. For the latter (semi-inclusive processes where, in addition to a charged lepton, final-state hadrons are detected), the concept of trajectories in the missing energy, missing momentum plane will be introduced. The importance of understanding the "nuclear landscape" in terms of these kinematic variables will be motivated.
Wednesday, May 3, 2017 | 10:30am, Room 310
The LHCb Experiment: Results and Prospects
Mike Williams, MITAbstract: The LHCb experiment, located at the LHC at CERN, has been the world's premier experiment for studying processes in which quark types (flavors) change since LHC Run 1 — and produced almost 400 papers to date. I will summarize the LHCb physics program, focusing on a few intriguing recent results, and discuss future prospects for both indirect and direct searches for physics beyond the Standard Model, and studies of emergent properties of the strong nuclear force (QCD).
-
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.
Unless otherwise noted, all seminars are held at Collaborative Learning and Innovation Complex (CLIC) - 574 Boston Avenue in Medford.
Thursday, September 15, 2016 | 10:30am, Room 114
"Say My Name": Neutrino physics through a quantum lens
Joseph Formaggio, MITAbstract: One of the most counter-intuitive aspects of quantum mechanics is the fact that the state of a particle is undetermined until it is measured. The Leggett-Garg inequality, an analogue of Bell's inequality involving correlations of measurements on a system at different times, provides a quantitative test of this unique property of quantum mechanics. The phenomenon of neutrino oscillations should adhere to quantum-mechanical predictions and provide an observable violation of the Leggett-Garg inequality. We demonstrate how oscillation phenomena can be used to test for violations of the classical bound by performing measurements on an ensemble of neutrinos at distinct energies, as opposed to a single neutrino at distinct times. A study of the MINOS experiment's data shows a greater than 6σ violation over a distance of 735 km, representing the longest distance over which either the Leggett-Garg inequality or Bell's inequality has been tested.
Thursday, October 13, 2016 | 10:30am, Room 114
Recursive Jigsaw Reconstruction in HEP complex event topologies
Christopher Rogan, Harvard UniversityAbstract: At the Large Hadron Collider (LHC), many new physics signatures feature pair-production of massive particles with subsequent direct or cascading decays to weakly interacting particles, such as SUSY scenarios with conserved R-parity or Higgs decaying to two leptons and two neutrinos through W bosons, often motivated by models of new physics which attempt to mitigate the hierarchy problem in the Standard Model. While final states containing multiple weakly interacting particles represent an opportunity for discovery of new physics phenomena, they also present a unique experimental challenge; the kinematic information lost through particles escaping detection makes fully reconstructing these collision events impossible. In order to address this shortcoming special kinematic variables are used to partially reconstruct these events, providing sensitivity to properties of the particles appearing in them, including masses and even their spin correlations. We introduce a systematic prescription, Recursive Jigsaw Reconstruction, for generating a preferred kinematic basis of kinematic variables developed to study final states with weakly interacting particles at HEP experiments, specifically catered to each case of interest. Using the examples of slepton pair-production at the LHC, the motivation and derivation of these observables are described along with comparisons to previously existing approaches. Generalizations to more complicated decay topologies are also discussed, including fully leptonic top quark pair production (resonant and non-resonant), its supersymmetric analogue of stop pair-production with subsequent decays to b-quarks, leptons, and neutrinos, and several examples involving both SM and BSM Higgs decays.
Thursday, November 17, 2016 | 10:30am, Room 114
Getting the most out of the LHC
Alan Barr, Oxford UniversityAbstract: Since you don't get many 27km accelerators to play with it makes sense to make good use of the one we've got. Using several case studies, I describe how new ideas in triggering, analysis and interpretation have made a real difference to what we can learn from world's leading collider.
Thursday, December 8, 2016 | 10:30am, Room 316
From Pixels to Neutrinos in MicroBooNE
Taritree Wongjirad, MITAbstract: The MicroBooNE experiment consists of a liquid argon time-projection chamber (LArTPC) that sits 470 m from the origin of the Booster Neutrino beam at Fermi National Lab. The goal of the experiment is to advance our knowledge of neutrino-nucleus cross sections and shed light on the MiniBooNE low energy anomaly. The latter is one of several anomalies seen in neutrino oscillation experiments that have been interpreted as hints for non-standard neutrinos. I will discuss the status of MicroBooNE and its achievements after one year of data taking. In particular, I will focus on one effort to use convolutional neural networks (CNNs) to reconstruct and select neutrino events. CNNs, a type of machine learning algorithm, are often the state-of-the-art approach in many computer vision tasks. For example, CNNs have found applications ranging from automated human face recognition to real-time object detection for self-driving cars. I'll describe our first steps in applying CNNs to the task of analyzing neutrino events in LArTPCs.