Related papers: Distinguishing `Higgs' Spin Hypotheses using gamma…
Studies of the spin, parity and tensor couplings of the Higgs boson in the $H\rightarrow ZZ^*\rightarrow 4\ell$, $H\rightarrow WW^* \rightarrow e\nu\mu\nu$ and $H\rightarrow \gamma \gamma$ decay processes at the LHC are presented. The…
The Higgs boson is predicted to have spin zero. The ATLAS and CMS experiments have recently reported of an excess of events with mass ~ 125 GeV that has some of the characteristics expected for a Higgs boson. We address the questions…
The LHC experiments ATLAS and CMS have discovered a new boson that resembles the long-sought Higgs boson: it cannot have spin one, and has couplings to other particles that increase with their masses, but the spin and parity remain to be…
A search for decays of the Higgs boson into a pair of new spin-zero particles, $H \to aa$, where the $a$-bosons decay into a $b$-quark pair and muon pair, is presented. The search uses 36.1 fb$^{-1}$ of proton-proton collision data at…
The new particle X recently discovered by the ATLAS and CMS Collaborations is widely expected to have spin zero, but this remains to be determined. The leading alternative is that X has spin two, presumably with graviton-like couplings. We…
Higgs decays to Z boson pairs may be exploited to determine spin and parity of the Higgs boson, a method complementary to spin-parity measurements in Higgs-strahlung. For a Higgs mass above the on-shell ZZ decay threshold, a…
Studies of the spin and parity quantum numbers of the Higgs boson are presented, based on proton-proton collision data collected by the ATLAS experiment at the LHC. The Standard Model spin-parity JP = 0+ hypothesis is compared with…
There is still no proof that the new particle $X$ recently discovered by the ATLAS and CMS Collaborations indeed has spin zero and positive parity, as confidently expected. We show here that the energy dependence of associated $W/Z + X$…
Searches are conducted for new spin-0 or spin-1 bosons using events where a Higgs boson with mass $125$ GeV decays into four leptons ($\ell =$ $e$,$\mu$). This decay is presumed to occur via an intermediate state which contains two…
A possibility to prove spin and CP-eigenvalue of a Standard Model (SM) Higgs boson is presented. We exploit angular correlations in the subsequent decay H -> ZZ -> 4l (muons or electrons) for Higgs masses above 200 GeV. We compare the…
There are many indirect and direct experimental indications that the new particle H discovered by the ATLAS and CMS Collaborations has spin zero and (mostly) positive parity, and that its couplings to other particles are correlated with…
Searches for the exclusive decays of the Higgs boson to an $\omega$ meson and a photon or a $K^{*}$ meson and a photon can probe flavour-conserving and flavour-violating Higgs boson couplings to light quarks, respectively. Searches for…
Whether the much studied X(3872) is an axial or tensor resonance makes an important difference to its interpretation. A recent paper by the BaBar collaboration raised the viable hypothesis that it might be a 2-+ state based on the 3 pions…
This paper presents a dedicated search for exotic decays of the Higgs boson to a pair of new spin-zero particles, $H \rightarrow aa$, where the particle $a$ decays to $b$-quarks and has a mass in the range of 20-60 GeV. The search is…
We chart the theoretical basis of radiative decays of the Higgs boson, $H \to \gamma\gamma$ and $Z\gamma$, for measuring the spin of the Higgs particle. These decay channels are complementary to other rare modes such as real/virtual…
A new boson around 125 GeV without specific spin has been observed by both ATLAS and CMS at the LHC. Since its decay into a diphoton excludes the spin-1 case by the Landau-Yang theorem,it leaves 0 or 2 as the possible lowest spin for the…
The observation of a new boson of mass $\sim 125\gev$ at the CERN LHC may finally have revealed the existence of a Higgs boson. Now we have the opportunity to scrutinize its properties, determining its quantum numbers and couplings to the…
This paper describes a search for beyond the Standard Model decays of the Higgs boson into a pair of new spin-0 particles subsequently decaying into $b$-quark pairs, $H \rightarrow aa \rightarrow (b\bar{b})(b\bar{b})$, using proton-proton…
A search for the decay of the Higgs boson to a $Z$ boson and a light, pseudoscalar particle, $a$, decaying respectively to two leptons and to two photons is reported. The search uses the full LHC Run 2 proton-proton collision data at…
This paper presents a search for exotic decays of the Higgs boson into a pair of new pseudoscalar particles, $H\rightarrow aa$, where one pseudoscalar decays into a $b$-quark pair and the other decays into a $\tau$-lepton pair, in the mass…