Contact
Name
Abideh Jafari
Position
Former member
Postdoc in CP3 from April 2014 to December 2016
Current position: Fellow at CERN.
Projects
I am involved in the following research directions:

Fast Simulation of the CMS experiment

A framework for Fast Simulation of particle interactions in the CMS detector (FastSim) has been developed and implemented in the overall simulation, reconstruction and analysis framework of CMS. It produces data samples in the same format as the one used by the Geant4-based (henceforth Full) Simulation and Reconstruction chain; the output of the Fast Simulation of CMS can therefore be used in the analysis in the same way as data and Full Simulation samples. FastSim is used in several physics analyses in CMS, in particular those requiring a generation of many samples to scan an extended parameter space of the physics model (e.g. SUSY) or for the purpose of estimating systematic uncertainties. It is also used by several groups to design future sub-detectors for the Phase-II CMS upgrades.
Related activities at UCL include the integration with the Full Simulation in the simulation of the electronic read-out ("digitization") and of the pileup of events from other proton-proton collisions, both in-time and out-of-time; the performance monitoring; and the overall maintenance and upgrade of the tracking-related code. Matthias Komm is current L3 convener of Tracking in FastSim, and Andrea Giammanco has been main responsible of the FastSim project from 2011 to 2013.

Search for exotic decays of the Higgs boson to a pair of new light bosons with two muons and two b jets in final states

We search for exotic decays of a Higgs boson to a pair of new light bosons, H->a1a1, where one of the light bosons decays to a pair of muons and the other one decays to a pair of b quarks. Such signatures are predicted in a number of well motivated extensions of the standard model, including the next-to-minimal supersymmetry and generic two Higgs doublet models with an additional scalar singlet.

Search for Higgs boson(s) in CMS at the LHC in the llbb topology

Search for Higgs boson(s) within the Standard Model and beyond and also withing a minimal extension of the scalar sector (2HDM).

The final state under study is a Z decaying into a lepton pair associated with two b-jets. This topology is sensitive to a light SM Higgs via the associate ZH production, as well as a middle mass range SM Higgs boson via the inclusive Higgs production followed by its decay into ZZ with one Z decaying into a lepton pair and the other into bbar.

It is also very sensitive to the production of a non standard heavy Higgs boson decaying into Z plus A (pseudo scalar Higgs boson).

Similar selection (but outside of the Z window) is also sensitive to H->aa->llbb, with "a" a generic light scalar.

External collaborators: CMS collaboration.

Single top studies at LHC

The electroweak production cross section of single top quarks is an important measurement for LHC, being a potential window on "new physics" effects.
Past achievements of this group include the very first measurement at 7 TeV (in t channel) with 2010 data, followed by the most precise inclusive cross section measurements of t-channel cross section at 7, 8 and 13 TeV, and the first differential measurements at 13 TeV; the most precise |Vtb| extraction from single top in the world; the first measurement of W-helicity fractions in a single-top topology; the first observation of the tW production mode; the first measurement of single-top polarization in t channel; stringent limits on anomalous tWb, tgu, tgc couplings.

External collaborators: CMS collaboration.

Past projects
Hide past projects.

I am involved in the following research directions:

Triggers for top quark physics

Our group is involved in the trigger design and maintenance for the LHC Run II in order to select the most interesting collision events for topologies with a lepton and a b quark with the CMS detector. Given the final state, this trigger is of particular interest for top quark physics, but it is also relevant to many other analyses (including the single top plus Higgs search ongoing in our group). Studies are carried out to implement the latest CMS developments in physics object definitions into the trigger path as well as to optimize the selections for the best efficiency and the rate possible. Our group is responsible for the b-tagging part together with organizing the whole activities within the CMS top quark group. Andrey Popov is official contact person between the Top Quark group and the Trigger group.

External collaborators: CMS TOP PAG, CMS TSG.

Publications in CP3
All my publications on Inspire

2017

The Phase-2 Upgrade of the CMS Tracker
CMS collaboration
[Full text] CERN-LHCC-2017-009 ; CMS-TDR-014
Refereed paper. 13th December.
Search for light bosons in decays of the 125 GeV Higgs boson in proton-proton collisions at sqrt(s) = 8 TeV
Khachatryan, Vardan and others
[Abstract] [PDF] [Journal]
Refereed paper. 10th January.

2016

Search for electroweak production of charginos in final states with two tau leptons in pp collisions at sqrt(s) = 8 TeV
CMS Collaboration
[Abstract] [PDF] [Journal] Submitted to JHEP
Report number: CMS-SUS-14-022, CERN-EP-2016-225

Refereed paper. 1st December.
Cross section measurement of $t$-channel single top quark production in pp collisions at $sqrt s =$ 13 TeV
Sirunyan, Albert M and others
[Abstract] [PDF] [Journal] Most precise measurement of the single-top cross section at 13 TeV.
Refereed paper. Public experimental note. 4th October.
Combination of cross-section measurements of associated production of a single top quark and a W boson at sqrt(s)=8 TeV with the ATLAS and CMS experiments
ATLAS and CMS collaborations
[Full text] ATLAS-CONF-2016-023 and CMS-PAS-TOP-15-019 (double reference, as it is a joint note)
Public experimental note. 24th May.
Measurement of the inclusive cross section of single top-quark production in the t-channel at 13 TeV
CMS collaboration
[Full text]
Public experimental note. 25th March.
Search for exotic decays of the Higgs boson to a pair of new light bosons with two muon and two b jets in final states
CMS Collaboration
[Full text]
Public experimental note. 3rd March.

2015

Measurement of the t-channel single top-quark cross section at 13 TeV
CMS collaboration
[Full text] Physics Analysis Summary TOP-15-004
Public experimental note. 14th September.
First look at top-quark selections with 13 TeV data
CMS collaboration
[Full text] CMS Detector Performance Note released in occasion of the EPS-HEP 2015 conference
Public experimental note. 24th July.

2014

Search for a non-standard-model Higgs boson decaying to a pair of new light bosons with two muon and two b jets in final states
Abideh Jafari and Andrea Giammanco
[Full text]
Private experimental note. 30th November.
Single top measurements and the |V_tb| extraction at the LHC
Abideh Jafari on behalf of the CMS and ATLAS collaborations
[Abstract] [PDF] To be appeared in the proceeding of the TOP2014 conference.
Contribution to proceedings. 30th November.
Measurement of the W boson helicity in events with a single reconstructed top quark in pp collisions at sqrt(s) = 8 TeV
Khachatryan, Vardan and others
[Abstract] [PDF] [Journal] [Full text] JHEP 01 (2015) 053
Refereed paper. 7th October.
Analysis of t-channel single top-quark production with Bayesian neural networks in CMS experiment at sqrt(s) = 7 TeV with L = 5/fb
E. Boos, V. Bunichev, L. Dudko, N. Tsirova, A. Markina, M. Perfilov, A. Popov, I. Myagkov, I. Shvetsov, G. Vorotnikov, S. Bitioukov, D. Konstantinov, A. Giammanco, J. Hansen, J. Komaragiri, D. Martschei, Th. Muller, J. Ott, T. Peiffer, S. Rocker, J. Wagner-Kuhr, A. O. M. Iorio, M. Merola, L. Lista, A. Jafari
[Full text] Analysis Note AN-2012/291 in support of CMS-TOP-14-007
Private experimental note. 12th June.
Measurements of the top-quark properties at CMS
Abideh Jafari for the CMS Collaboration
[Journal] [Full text] Proceedings of the Conference LHCP2013
Contribution to proceedings. 7th June.
W-helicity measurement in single-top event topology with lepton+jets final states using 19.7 fb^{-1} of LHC data collected by CMS at sqrt(s)=8 TeV
A. Jafari, A. O. Iorio, J. D'Hondt, J. Wagner Kuhr, L. Lista, R. Gonzalez Suarez, A. Giammanco
[Full text] CMS internal document supporting TOP-12-020 paper draft
Private experimental note. 7th June.

2013

Measurement of W-helicity fractions in single top events topology
CMS Collaboration
[Full text] CMS-TOP-12-020
Public experimental note. 7th March.


[UCLouvain] - [SST] [IRMP] - [SC]
Contact : Jérôme de Favereau
Research
Job opportunities EOS be.h : 10 PhD positions