Contact
Name
Andrey Popov
Position
Former member
PhD student in CP3 from November 2012 to October 2015
Current position: Postdoc at IPNL (Lyon, France).
Projects
I am involved in the following research directions:

#### 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.

#### Testing the sign of the coupling of the new H(125) boson to top quarks with the CMS data

During 2012, the CMS and ATLAS collaborations independently reported unambiguous evidence of the existence of a new particle of mass around 125 GeV.
Several analyses are ongoing to challenge the hypothesis that the new particle is the SM Higgs. We focus on the search for its production in association with a single top quark. Due to an effect of quantum interference, this process is strongly suppressed in the Standard Model while it gets enhanced if its couplings to the top quark and to the W boson have opposite sign. An observation of this production mode would therefore be a convincing proof that this new particle does not belong to the Standard Model.
We published the first search for this process using 8 TeV data, and we expect to achieve sensitivity to anomalous values of the top Yukawa phase during the LHC Run-II.

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

#### 2015

Search for the associated production of a Higgs boson with a single top quark in proton-proton collisions at $sqrt{s}=8$ TeV
Khachatryan, Vardan and others
[Abstract] [PDF] [Journal]
Refereed paper. 29th September.
First look at top-quark selections with 13 TeV data
CMS collaboration
CMS Detector Performance Note released in occasion of the EPS-HEP 2015 conference
Public experimental note. 24th July.

#### 2014

Identification of signal events in a search for H->bb produced in association with single top quarks
Andrey Popov on behalf of the CMS collaboration
[Abstract] [PDF] To appear in proceedings of TOP2014
Contribution to proceedings. 28th November.
Measurements of single top-quark production in pp collisions by the CMS experiment
Andrey Popov on behalf of the CMS collaboration
[Abstract] [PDF] To appear in proceedings of CKM2014
Contribution to proceedings. 28th November.
Search for $H\to b\bar b$ in association with single top quarks as a test of Higgs couplings
CMS Collaboration
CMS Physics Analysis Summary HIG-14-015
Public experimental note. 30th September.
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
Analysis Note AN-2012/291 in support of CMS-TOP-14-007
Private experimental note. 12th June.
Search for anomalous Wtb couplings and top FCNC in t-channel single-top-quark events
CMS Collaboration
CMS-PAS-TOP-14-007
Public experimental note. 9th June.
Search for H->bb in association with single top quarks as a test of Higgs boson couplings
A. Anuar, A. Bean, K. Bloom, C. Boeser, T. Chwalek, S. Fink, A. Giammanco, R. Gonzalez Suarez, D. Knowlton, J. Komaragiri, M. Komm, B. Maier, D. Noonan, A. Popov, J. Wagner-Kuhr
Analysis Note AN-2013/113 in support of CMS-HIG-14-015
Private experimental note. 7th June.

#### 2013

Measurement of top quark polarization in t-channel single-top production
T. Chwalek, A. Giammanco, A. O. M. Iorio, M. Kadastik, M. Komm, D. Konstantinov, J. Pata, M. Piibeleht, A. Popov, L. Rebane, A. Remm, S. Roecker, A. Tiko, F. Roscher, J. Wagner-Kuhr
Supporting note for CMS-TOP-13-001
Private experimental note. 23rd September.

Contact : Jérôme de Favereau