Dr Kostas Nikolopoulos

 

Lecturer
Birmingham Fellow

School of Physics and Astronomy

Dr Kostas Nikolopoulos

Contact details

Physics and Astronomy
University of Birmingham
Edgbaston
Birmingham
B15 2TT
UK

About

Kostas Nikolopoulos’ is interested in the experimental study of the electroweak symmetry breaking and the Higgs sector, at the ATLAS experiment at the CERN Large Hadron Collider. He led the ATLAS H→ZZ group between October 2010 and October 2012, in the effort that resulted in the discovery of a Standard Model-like Higgs boson. Currently, his research is focusing on the detailed study of the properties  of the newly observed particle and searches for its, potentially, anomalous rare decays, as well as, on searches for additional Higgs bosons.

He is increasingly involved in teaching at undergraduate and graduate levels in physics and he is involved in outreach activities.

Qualifications

 

  • PhD in Particle Physics, University of Athens, 2010

Biography

Kostas Nikolopoulos obtained his Ph.D. on the ATLAS experiment with the University of Athens (Greece) in 2010. His thesis was awarded Marc Virchaux Prize. Subsequently, he joined the Brookhaven National Laboratory (USA) as a post-doctoral research associate, and since 2012 he joined the University of Birmingham as a Lecturer and Birmingham Fellow. In October 2014, he was elected ATLAS UK Physics coordinator.

Became heavily involved in the H→ZZ*→4l analysis already before data-taking, developing the tools and strategies that were used in the actual data analysis. In Oct 2010 he was appointed convener of the ATLAS H → ZZ group (Higgs boson decays channels involving Z bosons), consisting of more than 100 physicists. His term of office was exceptionally extended (Oct 2011) for an additional year and he led the group in the discovery of Higgs boson-like particle in July 2012. Subsequently, he turned his attention to the study of the properties of the Higgs boson with emphasis on the mass, production rates, and couplings. He introduced analysis categories with topologies sensitive to the Higgs boson production mechanism, and experimental variables that enhanced the sensitivity to coupling properties through multi-observable maximum-likelihood fits. This culminated in several publications establishing the Standard Model-like character of the observed Higgs boson.

Furthermore, he is interested in searches for physics Beyond the Standard Model in the Higgs sector; both through the search for additional Higgs boson and through anomalous decays of the observed Higgs boson. He has led the team that performed the first search for the decay of the Higgs boson to a quarkonium state and a photon (H → J/ψγ and H → Υγ), as well as the previously unobserved analogous decays of the Z boson. This analysis provides first information on the Yukawa coupling of the charm quark.

Kostas is a co-investigator on the Birmingham Particle Physics grant from the Science and Technology Facilities Council (STFC).

In recent years has also received funding in support of his work from the Marie Curie actions and the Durham Institute of Particle Physics Phenomenology. 

Teaching

  • Y3 Laboratory: "Nuclear Laboratory"
  • MPAGS Course: "Higgs Boson Physics"
  • MPAGS Course: "Particle Physics Methods

Postgraduate supervision

Currently working with PhD students on the ATLAS experiment at CERN.

Research

Research themes

  • Study of the properties of the observed Standard Model-like Higgs boson
  • Searches for rare decays of the observed Standard Model-like Higgs boson
  • Searches for additional Higgs bosons

Research Activity

  • ATLAS experiment at CERN

Other activities

Outreach; including the "Higgs boson and beyond" exhibit at the Royal Society Science Exhibition in 2014.

Publications

Selected Publications: 

  • ATLAS Collaboration (2015), Search for Higgs and Z Boson Decays to J/ψγ and Y(nS)γ with the ATLAS Detector, Phys. Rev. Lett. 114 121801.
  • ATLAS Collaboration (2015), Measurements of Higgs boson production and couplings in the four-lepton channel in pp collisions at center-of-mass energies of 7 and 8 TeV with the ATLAS detector, Phys. Rev. D91 012006.
  • ATLAS Collaboration (2014), Fiducial and differential cross sections of Higgs boson production measured in the four-lepton decay channel in pp collisions at √s = 8 TeV with the ATLAS detector, Phys. Lett. B738 (2014) 234-253
  • ATLAS Collaboration (2014), Measurement of the Higgs boson mass from the H→γγ and H→ZZ*→4l channels with the ATLAS detector at the LHC, Phys. Rev. D90 052004.>
  • ATLAS Collaboration (2013), Measurements of Higgs production and couplings using diboson final states with the ATLAS detector at the LHC, Phys. Lett. B 726 88-119.
  • ATLAS Collaboration (2013), Evidence for the spin-0 nature of the Higgs boson using ATLAS data, Phys. Lett. B 726 120-144.
  • ATLAS Collaboration (2012), Observation of a new particle in the search for the Standard Model Higgs boson with the ATLAS detector at the LHC, Phys. Lett. B716 1-29.
  • ATLAS Collaboration (2012), Combined search for the Standard Model Higgs boson using up to 4.9 fb^{-1} of pp collision data at √s = 7 TeV with the ATLAS detector at the LHC, Phys. Lett. B710 49-66.
  • ATLAS Collaboration (2012), Search for the Standard Model Higgs boson in the decay channel H→ ZZ* → 4l with 4.8 fb−1 of pp collisions at √s = 7 TeV with ATLAS, Phys. Lett. B710 383-402.
  • ATLAS Collaboration (2012), Search for a heavy Standard Model Higgs boson in the channel H→ ZZ → llqq using the ATLAS detector, Phys. Lett. B707 27-45.
  • ATLAS Collaboration (2011), Search for the Standard Model Higgs boson in the decay channel H → ZZ*  → 4l with the ATLAS detector, Phys. Lett. B705 435-451.
  • ATLAS Collaboration (2011), Search for a Standard Model Higgs boson in the mass range 200-600 GeV in the H → ZZ → llνν decay channel with the ATLAS Detector, Phys. Rev. Lett. 107 221802. 
  • ATLAS Collaboration (2011), Limits on the production of the Standard Model Higgs Boson in pp collisions at √s = 7 TeV  with the ATLAS detector, Eur. Phys. J. C 71, 1728.

Expertise

Particle physics experiments; CERN; LHC; Higgs physics.

Alternative contact number available for this expert: contact the press office

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