We describe recent developments of the public computer code HiggsBounds. In particular, these include the incorporation of LHC Higgs search results from Run 2 at a center-of-mass energy of 13 TeV, and an updated and extended framework for the theoretical input that accounts for improved Higgs cross section and branching ratio predictions and new search channels. We furthermore discuss an improved method used in HiggsBounds to approximately reconstruct the exclusion likelihood for LHC searches for non-standard Higgs bosons decaying to $$\tau \tau $$
 final states. We describe in detail the new and updated functionalities of the new version HiggsBounds-5.

/pdf/higgsbounds-5-testing-higgs-sectors-in-the-lhc-13-tev-era-1dzhoobpre.pdf

HiggsBounds-5: testing Higgs sectors in the LHC 13 TeV Era

https://bura.brunel.ac.uk/bitstream/2438/18651/1/FullText.pdf

Search for an exotic decay of the Higgs boson to a pair of light pseudoscalars in the final state with two muons and two b quarks in pp collisions at 13 TeV

Light new physics weakly coupled to the Higgs can induce a strong first-order electroweak phase transition (EWPT). Here, we argue that scenarios in which the EWPT is driven first-order by a light scalar with mass between $\ensuremath{\sim}10\text{ }\text{ }\mathrm{GeV}\ensuremath{-}{m}_{h}/2$ and small mixing with the Higgs will be conclusively probed by the high-luminosity LHC and future Higgs factories. Our arguments are based on analytic and numerical studies of the finite-temperature effective potential and provide a well-motivated target for exotic Higgs decay searches at the LHC and future lepton colliders.

/pdf/exotic-higgs-boson-decays-and-the-electroweak-phase-29z8wt9ll1.pdf

Exotic Higgs boson decays and the electroweak phase transition

https://repository.hanyang.ac.kr/bitstream/20.500.11754/160859/1/Search%20for%20light%20pseudoscalar%20boson%20pairs%20produced%20from%20decays%20of%20the%20125%20GeV%20Higgs%20boson%20in%20final%20states%20with%20two%20muons%20and%20two%20nearby%20tracks%20in%20pp%20collisions%20at%20root%20s%20d%3d13TeV.pdf

Search for light pseudoscalar boson pairs produced from decays of the 125 GeV Higgs boson in final states with two muons and two nearby tracks in pp collisions at s=13TeV

Abstract A search for an exotic decay of the Higgs boson to a pair of light pseudoscalar bosons is performed for the first time in the final state with two b quarks and two τ leptons. The search is motivated in the context of models of physics beyond the standard model (SM), such as two Higgs doublet models extended with a complex scalar singlet (2HDM + S), which include the next-to-minimal supersymmetric SM (NMSSM). The results are based on a data set of proton–proton collisions corresponding to an integrated luminosity of 35.9 fb − 1 , accumulated by the CMS experiment at the LHC in 2016 at a center-of-mass energy of 13 TeV . Masses of the pseudoscalar boson between 15 and 60 GeV are probed, and no excess of events above the SM expectation is observed. Upper limits between 3 and 12% are set on the branching fraction B ( h → a a → 2 τ 2 b ) assuming the SM production of the Higgs boson. Upper limits are also set on the branching fraction of the Higgs boson to two light pseudoscalar bosons in different 2HDM + S scenarios. Assuming the SM production cross section for the Higgs boson, the upper limit on this quantity is as low as 20% for a mass of the pseudoscalar of 40 GeV in the NMSSM.

Search for an exotic decay of the Higgs boson to a pair of light pseudoscalars in the final state with two b quarks and two τ leptons in proton–proton collisions at √s = 13 TeV

http://sedici.unlp.edu.ar/bitstream/handle/10915/79871/Documento_completo.pdf?sequence=1

Search for Higgs boson decays into a pair of light bosons in the bbμμ final state in pp collision at √s=13TeV with the ATLAS detector

Parameterization above (or below) a guarantee is a successful concept in parameterized algorithms. The idea is that many computational problems admit ``natural'' guarantees bringing to algorithmic questions whether a better solution (above the guarantee) could be obtained efficiently. The above guarantee paradigm has led to several exciting discoveries in the areas of parameterized algorithms and kernelization. We argue that this paradigm could bring forth fresh perspectives on well-studied problems in approximation algorithms. Our example is the longest cycle problem. One of the oldest results in extremal combinatorics is the celebrated Dirac's theorem from 1952. Dirac's theorem provides the following guarantee on the length of the longest cycle: for every 2-connected n-vertex graph G with minimum degree \delta(G)\leq n/2, the length of a longest cycle L is at least 2\delta(G). Thus, the ``essential'' part in finding the longest cycle is in approximating the ``offset'' k = L - 2 \delta(G). The main result of this paper is the above-guarantee approximation theorem for k. Informally, the theorem says that approximating the offset k is not harder than approximating the total length L of a cycle. In other words, for any (reasonably well-behaved) function f, a polynomial time algorithm constructing a cycle of length f(L) in an undirected graph with a cycle of length L, yields a polynomial time algorithm constructing a cycle of length 2\delta(G)+\Omega(f(k)).

Fedor Fomin

Papers

Search for Higgs boson decays into a pair of light bosons in the bbμμ final state in pp collision at √s=13TeV with the ATLAS detector

Approximating Long Cycle Above Dirac's Guarantee