Spring 2014

The couplings between the Higgs and fermionic fields can be accessed directly through processes in which the Higgs boson decays into fermions, or is produced in association with a top-quark pair. Several analyses based on the full dataset collected by CMS at 7 and 8 TeV are presented. In particular, the final results of searches for a Higgs boson decaying into a b-quark or a tau-lepton pair are presented, together with a preliminary combination of these results.

While the observation of neutrino oscillations tells us that there are nonzero neutrino mass splittings, oscillations in vacuum do not easily reveal the signs of these splittings. Knowledge of this neutrino “mass hierarchy” may help solve other fundamental questions about neutrinos, the origin of their mass, and physics beyond the Standard Model. One mass splitting hierarchy, between m1 and m2, was determined through observations of solar neutrino flavor change and the understanding of Mikheyev-Smirnov-Wolfenstein resonance within the sun. The larger hierarchy, with m3, may be resolved by observing the effect of matter interactions with the Earth, which result in still different oscillation phenomena. I will present an overview of the theory of neutrino oscillations in matter and the variety of experiments which are pursuing this approach to ascertain the neutrino mass hierarchy.

In this book review, I'll walk through the ideas presented in "The Foundations of Scientific Inference" (1967), the first text written by the recently deceased Dr. Wesley Salmon. While the core of the talk will focus on Hume's "problem of induction," it will also touch on distinctions between Bayesian and frequentist conceptions of probability, and we may attempt to answer the question: can a scientific approach ever actually yield new knowledge? This inquiry will reflect a serious concern for the most compulsive among us and a lighthearted thought experiment for the rest.

Heavy ion collisions at the LHC have been predicted to produce a new state of matter similar to the Quark Gluon Plasma believed to have existed fractions of a second after the big bang. The study of hadron correlations is used to study the "flow" of particles in this hot dense medium. A recent discovery by the MIT heavy ion group of an unusually high elliptic component of the flow was contrary to all precious theoretical predictions. This talk will introduce the technique of 2-particle correlations in heavy ion collisions, and further discuss how identified particles, and the phi meson in particular can be used to further understand the collective behavior of particles in heavy ion collisions

Internet security becomes a hot topic after the NSA leak by Edward Snowden last year, before the success of creating quantum computer, the only way to protect people's privacy on the Internet is through cryptographic applications. I will talk about some basic knowledge of cryptography, with discussions of a few famous cryptographic algorithms, from the perspectives of both mathematics and programming. In the end I will briefly discuss possible ways of effectively implementing cryptography to Internet security applications.

A high-density colour-deconfined state of strongly-interacting matter is expected to be formed in high energy collisions of heavy nuclei. According to QCD on the lattice, under these conditions, a phase transition to a Quark-Gluon Plasma (QGP) occurs. Heavy-flavour hadrons, containing charm and beauty, are effective probes of the conditions of the medium formed in nucleus-nucleus collisions at high energy. The special role of heavy flavour in the study of QGP will be introduced, and results from different experiments will be presented.

I will give an introduction of my undergrad research projects. In the talk, the studies of missing transverse energy (E_T^miss) in H→W⁺W^-→lνlν decay mode will be presented using 21 fb^-1 proton-proton collisions at √ s = 8 TeV collected with the ATLAS detector at the LHC. I will also talk about related fake missing transverse energy behavior using Z→μμ events.

This talk will describe progress on establishing a lightguide-based light collection system for LArTPCs, including the LAr1 and LBNE experiments. Recent developments have resulted in over an order of magnitude improvement in these detectors compared to the first published systems.

The OLYMPUS Experiment, which completed data taking in 2013, will determine the ratio of positron-proton to electron-proton elastic scattering cross sections over a range of momentum transfer from 0.4 to 2.2 (GeV/c)2. A deviation in this ratio from unity is evidence of two-photon exchange, which is a possible explanation for the discrepancy in measurements of the proton's electromagnetic form factors. However, the ratio is also sensitive to other radiative effects, such as the interference of lepton and proton bremsstrahlung. To isolate the contribution of hard two-photon exchange, the OLYMPUS MIT group has developed a Monte Carlo radiative generator, so that the various contributions to the cross section ratio can be studied by simulation. With this method, radiative effects can be properly convolved with detector-specific properties such as acceptance and efficiency. It is a goal of the collaboration to make this generator publicly available so that unbiased comparisons can be made between OLYMPUS and other two-photon exchange experiments. The MIT generator will be presented in detail along with a description of radiative corrections in the OLYMPUS analysis.

This talk describes a method for inducing charge on a wire plane by pulsing a capacitively coupled antenna. This is designed to aid other systems in diagnosing wire integrity. Results from studying a prototype with the MicroBooNE TPC will be presented.

In ultrarelativistic heavy-ion collisions studied at the LHC, observation of centrality dependent transverse momentum imbalance in dijet events beyond that observed in pp collisions suggests partons lose energy traversing the medium created, known as the Quark-Gluon Plasma (QGP). In this talk, I will review past studies with the CMS detector of the observed jet quenching using missing transverse momentum techniques analogous to those used in reconstructing neutrinos. Missing momentum of the subleading jet is recovered through low momentum particles distributed over a much larger angular range than that of the leading jet. I will conclude with some discussion of ongoing studies with greater statistics, which expands on the angular distribution of varying momentum particles and examines asymmetry in multiplicity of particles towards leading and subleading jets.

This practice will have no assigned topic. Bring a good exam question with you.

I'll give an overview of particle flow correlations and in heavy ion collisions, and talk about how we are adapting this analysis for proton-proton events. I'll show some surprising results from the last LHC run, and outline some effects that we plan to measure in the future, including a search for v3.

Quarkonium are flavorless mesons form by heavy quarks (c and b quarks). The first observed quarkonium is the well known J/psi and since that, exploding efforts from both theoretical and experimental were made during that era. I will try to briefly mention a few experiment results related and some early theory paper as well as the an introduction of "nonrelativistic quantum chromodynamic" (NRQCD).

Topic: Particle electric dipole moments

Precision measurements of the anti-hydrogen spectrum can be used to probe CPT invariance. I will discuss current experiments and prospects for antihydrogen studies.