Abstract
A search for the exclusive decays of the Higgs and Z bosons to a ϕ or ρ meson and a photon is performed with a pp collision data sample corresponding to an integrated luminosity of up to 35.6 fb−1 collected at sqrt{s}=13 TeV with the ATLAS detector at the CERN Large Hadron Collider. These decays have been suggested as a probe of the Higgs boson couplings to light quarks. No significant excess of events is observed above the background, as expected from the Standard Model. Upper limits at 95% confidence level were obtained on the branching fractions of the Higgs boson decays to ϕγ and ργ of 4.8 × 10−4 and 8.8 × 10−4, respectively. The corresponding 95% confidence level upper limits for the Z boson decays are 0.9 × 10−6 and 25 × 10−6 for ϕγ and ργ, respectively.
Highlights
For both the φγ and ργ final states, the main sources of background in the searches are events involving inclusive photon + jet or multijet processes where an M candidate is reconstructed from inner tracking detector (ID) tracks originating from a jet.From the selection criteria discussed earlier, the shape of this background exhibits a turn-on structure in the mMγ distribution around 100 GeV, in the region of the Z boson signal, and a smoothly falling background in the region of the Higgs boson signal
This paper describes a search for Higgs boson decays into the exclusive final states φγ and ργ
In the absence of appropriate simulations, pseudocandidate events are generated, from which the background shape in the discriminating variable is derived. This ensemble of pseudocandidate events is produced by randomly sampling the distributions of the relevant kinematic and isolation variables, which are estimated from the data in the generation region” (GR)
Summary
ATLAS [30] is a multi-purpose particle physics detector with a forward-backward symmetric cylindrical geometry and near 4π coverage in solid angle. It consists of an inner tracking detector surrounded by a thin superconducting solenoid, electromagnetic and hadronic calorimeters, and a muon spectrometer. ATLAS [30] is a multi-purpose particle physics detector with a forward-backward symmetric cylindrical geometry and near 4π coverage in solid angle.. ATLAS [30] is a multi-purpose particle physics detector with a forward-backward symmetric cylindrical geometry and near 4π coverage in solid angle.1 It consists of an inner tracking detector surrounded by a thin superconducting solenoid, electromagnetic and hadronic calorimeters, and a muon spectrometer. The inner tracking detector (ID) covers the pseudorapidity range |η| < 2.5, and is surrounded by a thin superconducting solenoid providing a 2 T magnetic field. A high-granularity silicon pixel detector covers the vertex region and typically provides three measurements per track. The pixel detectors are followed by a silicon microstrip tracker, which typically provides four space-point measurements per track. It is followed by a software-based highlevel trigger which filters events using the full detector information and records events for detailed offline analysis at an average rate of 1 kHz
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
