Nuclear and Particle Physics

Searching for pair production of Higgs bosons in the bbtautau final state with the ATLAS detector

Name: Searching for pair production of Higgs bosons in the bbtautau final state with the ATLAS detector
Start: 2020-04-23T10:30:00+02:00
End: 2020-04-23T12:30:00+02:00
Location: Zoom

by Petar Bokan (Uppsala University)

Thursday 23 Apr 2020, 10:30 → 12:30 Europe/Stockholm

686 2959 4539 (Zoom)

686 2959 4539

Zoom

Zoom Meeting https://uu-se.zoom.us/j/68629594539 Meeting ID: 686 2959 4539 One tap mobile +46850500828,,68629594539# Sweden +46850500829,,68629594539# Sweden Dial by your location +46 8 5050 0828 Sweden +46 8 5050 0829 Sweden +46 8 5052 0017 Sweden +46 850 539 728 Sweden +46 8 4468 2488 Sweden +45 32 71 31 57 Denmark +45 32 72 80 10 Denmark +45 32 72 80 11 Denmark +45 89 88 37 88 Denmark +45 32 70 12 06 Denmark +47 7349 4877 Norway +47 2396 0588 Norway +49 30 5679 5800 Germany +49 695 050 2596 Germany +49 69 7104 9922 Germany +33 1 7037 9729 France +33 1 7095 0103 France +33 1 7095 0350 France +33 7 5678 4048 France +33 1 7037 2246 France +44 208 080 6591 United Kingdom +44 208 080 6592 United Kingdom +44 330 088 5830 United Kingdom +44 131 460 1196 United Kingdom +44 203 481 5237 United Kingdom +44 203 481 5240 United Kingdom +1 646 876 9923 US (New York) +1 669 900 6833 US (San Jose) +1 253 215 8782 US +1 301 715 8592 US +1 312 626 6799 US (Chicago) +1 346 248 7799 US (Houston) +1 408 652 8184 US (San Jose) Meeting ID: 686 2959 4539 Find your local number: https://uu-se.zoom.us/u/cNamzXf Join by SIP 68629594539@109.105.112.236 68629594539@109.105.112.235 Join by H.323 109.105.112.236 109.105.112.235 Meeting ID: 686 2959 4539 Join by Skype for Business https://uu-se.zoom.us/skype/68629594539

Description

This will be our first virtual seminar, and will be hosted in Zoom

Meeting ID: 686 2959 4539

Direct link: https://uu-se.zoom.us/j/68629594539

Final PhD seminar

Abstract:

After the discovery of the Higgs boson, the ultimate test of the electroweak symmetry breaking is to establish evidence of Higgs boson self-coupling, which can be achieved by searching for pair production of Higgs bosons (di-Higgs). In the Standard Model (SM), di-Higgs is dominantly produced in the gluon-gluon fusion processes, namely via the loop of top-quarks (Yukawa coupling), or the Higgs boson self-coupling. These two production mechanisms interfere destructively, which leads to a very small di-Higgs production cross-section. It is not expected that the data recorded during the Run 2 of the LHC will be enough to observe di-Higgs if there are no deviations from the SM couplings. On the other hand, deviations in couplings of the Higgs boson could lead to a significant enhancement of the di-Higgs production rate. In addition, many beyond the SM (BSM) theories predict heavy resonances that would decay into pairs of SM Higgs bosons.

A search for non-resonant and resonant di-Higgs production in the bbττ channel is presented for 36.1 /fb of sqrt{s} = 13 TeV data recorded at the ATLAS experiment at the LHC. The observed (expected) upper limit on the non-resonant Higgs boson pair production cross-section times branching ratio corresponds to 12.7 (14.8) times the SM prediction. The ratio of the Higgs boson self-coupling to its SM expectation, κ_λ , is observed (expected) to be constrained at 95% CL to -7.3 < κ_λ < 15.7 (-8.8 < κ_λ < 16.7). The sensitivity is extrapolated to a 14 TeV center-of-mass energy and 3000 /fb, which is the target integrated luminosity of the High-Luminosity LHC. Various extrapolation assumptions are taken into account. Furthermore, potential improvements of the analysis techniques are discussed in the context of achieving even higher sensitivity with the full Run 2 data recorded by the ATLAS experiment.