相关论文: Discovering the top partners at the LHC using same…
Search for the Higgs Boson is one of the prime goals of the LHC. Higgs bosons lighter than 130 GeV decay mainly to a b-quark pair. While the detection of a directly produced Higgs boson in the bb channel is impossible because of the huge…
Current searches for the light top squark (stop) mostly focus on the decay channels of $\tilde{t} \rightarrow t \chi_1^0$ or $\tilde{t} \rightarrow b \chi_1^\pm \rightarrow bW \chi_1^0$, leading to $t\bar{t}/bbWW+\met$ final states for stop…
We assess how different ATLAS and CMS searches for supersymmetry in the $t\bar t + E_T^{\rm miss}$ final state at Run 1 of the LHC constrain scenarios with a fermionic top partner and a dark matter candidate. We find that the efficiencies…
We present searches for massive top and bottom quark partners at CMS using LHC pp collision data collected at centre-of-mass energy $\sqrt{s} = 8$ TeV. Such partners can be found in models predicting vector-like quarks to solve the…
With the upgrade of the LHC, the couplings of the observed Higgs particle to fermions and gauge bosons will be measured with a much higher experimental accuracy than current measurements, but will still be limited by an order 10%…
Six top signatures provide a novel probe of new physics. We discuss production of six top quarks as the decay products of a pair of top partners in the setting of a composite Higgs model, and argue that the six top signal may generically…
The possibility of a vectorlike top partner decaying to a new colourless weak-singlet scalar or pseudoscalar has attracted some attention in the literature. We investigate the production of a weak-singlet charge-$2/3$ $T$ quark that can…
Two of the most important parameters in supersymmetry are the masses of the stop and sbottom, the supersymmetric partners of the third generation quarks. A stop mass lighter than 1 TeV is favored theoretically, however, conventional…
A possible composite nature of the Higgs could be revealed at the early stage of the LHC, by analyzing the channels where the Higgs is produced from the decay of a heavy fermion. The Higgs production from a singly-produced heavy bottom, in…
A search is presented for same-sign top-quark production and down-type heavy quarks of charge -1/3 in events with two isolated leptons (electrons or muons) that have the same electric charge, at least two jets and large missing transverse…
In this work, we have considered an extension of the standard model (SM) with a $SU(2)_L$ singlet vectorlike quark (VLQ) with electric charge $Q=+2/3$. The model also contains an additional local $U(1)_d$ symmetry group and the…
Fermion masses may arise via mixing of elementary fermions with composite fermions of a strong sector in scenarios of strongly-coupled electroweak symmetry breaking. The strong sector may contain leptoquark states with masses as light as…
We study the LHC signal of a light gluino whose cascade decay is dominated by channels involving top, and, sometimes, bottom quarks. This is a generic signature for a number of supersymmetry breaking scenarios considered recently, where the…
A search for the associated production of the Higgs boson with a top quark pair is performed in multilepton final states using 20.3 fb$^{-1}$ of proton-proton collision data recorded by the ATLAS experiment at $\sqrt{s}=8$ TeV at the Large…
Imagine to discover a new fourth family of leptons at the Large Hadron Collider (LHC) but no signs of an associated fourth family of quarks. What would that imply? An intriguing possibility is that the new fermions needed to compensate for…
The results of a search for pair production of a heavy, top-like quark, t', in the decay mode (t' anti-t') to (b anti-W anti-b W) to (b anti-lepton neutrino anti-b lepton anti-neutrino) are presented. The search is performed with a data…
This paper investigates the $e^-e^+\to Zh_1$ sensitivity for Higgs boson's rare decay into heavy neutrinos $h_1 \to NN$ at the proposed electron-positron collider, with the focus on multi-lepton final states that contain same-sign lepton…
A search is presented for direct pair production of the stop, the supersymmetric partner of the top quark, in a decay through an $R$-parity violating coupling to a charged lepton and a $b$-quark. The dataset corresponds to an integrated…
We report the result of a search for the pair production of the lightest supersymmetric partner of the top quark ($\tilde{t}_1$) in $p\bar{p}$ collisions at a center-of-mass energy of 1.96 TeV at the Fermilab Tevatron collider corresponding…
The standard-model Higgs boson couples to quarks through a parity-even scalar $Hq{\bar q}$ coupling. We show that the rare Higgs decay $H\to VZ$, where $V$ is a vector quarkonium state such as $J/\psi$ ($c{\bar c}$) or $\Upsilon(1S)$…