Elementary Particle Physics Seminar

semester, 2018

Wednesday, January 10th 2018
Speaker:  Jaebak Kim, Korea University
Subject:  Search for CP violation using T-odd correlations in D0 → K+K−π+π− decay / The 3-dimensional level one track trigger for the Belle II experiment

We search for CP violation using T-odd correlation in the singly Cabbibo suppressed D0 -> K+K-pi+pi- decay at the KEKB asymmetric e+e- collider. The D+- particles are reconstructed to tag the D0 particles and a triple product using the momentum of the D0's daughter particles is calculated. Cuts and vetos are applied to the reconstructed sample. A two dimensional simultaneous fit using four sub-samples depending on the triple product and D0 flavor while using the invariant mass of D0 and the invariant mass difference between D+ and D0 particles as the two dimensions is performed. The T-odd correlation and systematics are calculated.

The next generation e+ e- collision experiment called Belle II will start colliding particles this year. It will search for new physics using high precision measurements which were not possible before. The precision will be achieved by using a high luminosity beam. Due to the luminosity of the beam, there must be an fast and efficient trigger system in order to record the physics relevant data. The Belle II level 1 trigger system is a combination of sub-trigger FPGA based systems, where the main triggers are the central drift chamber (CDC) trigger and electromagnetic calorimeter detector trigger (ECL) trigger. Between them the CDC trigger finds the momentum and vertex position of charged tracks. These precise information will then be used to determine whether the event has
interesting physics or not. If the event is determined to be physics relevant, the DAQ system will record the detector data to disk. The level 1 CDC trigger consists of 7 types of boards. They are the Frontend boards, Merger boards, TSF boards, 2D finder board, Event time finder board, 3D tracker boards, and Neural Network boards. Each board has a specific function that makes tracking charged track possible with high precision.

Wednesday, January 17th 2018
3:35 pm:
To be announced.

Wednesday, January 24th 2018
Speaker: Dr. Shilpi Jain. National Central University Taiwan.
Subject: Search for H-->Zgamma—>llgamma with the CMS detector
Note change of time and room from previous announcement.

Jain will talk about the search for a Higgs boson decaying into a Z boson and a photon. The analysis is performed using a dataset recorded by the CMS experiment at the LHC from proton-proton collisions at a centre-of-mass energy of 13 TeV corresponding to an integrated luminosity of 35.9 fb-1. Limits are set on the cross section of a standard model Higgs boson decaying to electron or muon pairs and a photon. The expected exclusion limits at 95% confidence level are between 9 and 4 times the standard model cross section in the mass range of 120 and 130 GeV.

Wednesday, January 31st 2018
3:35 pm:
To be announced.

Wednesday, February 7th 2018
Speaker: Yassin Haddad, Imperial College London
Subject: Latest Results on Higgs to Diphotons from CMS

The most-recent results on Higgs to diphotons measurements from CMS will be reviewed. (Speaker is a candidate for a postdoctoral research position and will be presenting by video)

Wednesday, February 14th 2018
To be announced.

Wednesday, February 21st 2018
To be announced.

Wednesday, February 28th 2018
Speaker:  Hajime Muramatsu, University of Minnesota
Subject: Leptonic Decays of Charmed Mesons at BESIII

BESIII now holds the world's largest e+e- annihilation samples taken at Ecm = 3.773 and 4.178 GeV which produce copious charmed mesons, D0, D+, and Ds+. In this talk, I report our on-going studies on D+ -> l nu and Ds -> l nu (l = mu and tau). These allow us to determine the elements of the CKM matrix within the standard model, to test the unitarity of the second rows of the CKM matrix, probe lepton universality, as well as to calibrate the LQCD calculations of the decay constants, fD(s)+.

Wednesday, March 7th 2018
To be announced.

Wednesday, March 21st 2018
To be announced.

Wednesday, March 28th 2018
To be announced.

Wednesday, April 4th 2018
To be announced.

Wednesday, April 11th 2018
Speaker: Ruchi Gupta, Southern Methodist University
Subject: Measurement of gluon fusion and vector boson fusion Higgs boson production cross-sections in the H→ WW*→ eνμν decay channel in pp collisions at sqrt(s) = 13 TeV

The Higgs boson production cross-sections in proton-proton collisions are measured using the events in the H→WW*→eνμν decay channel. The measured cross sections probe the Higgs boson couplings to heavy bosons and to gluons. The proton-proton collision data were produced at the Large Hadron Collider at a centre-of-mass energy of 13 TeV and recorded by the ATLAS detector in 2015 and 2016, corresponding to an integrated luminosity of 36.1 fb−1.

Wednesday, April 18th 2018
To be announced.

Wednesday, May 2nd 2018
Speaker: Michael Krohn, University of Colorado
Subject: Utilizing Boosted Higgs Bosons at CMS

Wednesday, May 9th 2018
There will be no seminar this week.

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