The strong constraints on the R-parity conserving supersymmetry (SUSY) from the LHC searches motivate us to consider the new models in which the low-scale SUSY is still allowed. We propose a kind of ...R-parity violating SUSY scenario with a nonzero U2cD2cD3c operator. Three relevant LHC searches are recast to test the status of this scenario in terms of four simplified models, with either light stop-Bino, stop-Higgsino, sbottom-Bino, or sbottom-Higgsino. Some difficult scenarios for the LHC SUSY searches in these simplified models are identified. By extrapolating the current LHC searches to the future 14 TeV LHC with integrated luminosity of 3000 fb−1, the stop/sbottom masses in all scenarios can be probed up to ∼800–1100 GeV.
A quirk propagating through a detector is subject to the Lorentz force, a new confining gauge force, and the frictional force from ionization energy loss. At the LHC, it was found that the monojet ...search and the coplanar search were able to constrain such a quirk signal. Inspired by the coplanar search proposed by Knapen et al. Phys. Rev. D 96, 115015 (2017), we develop a new search that also utilizes the information of the relatively large ionization energy loss inside the tracker. Our algorithm has improved efficiency in finding quirk signals with a wide oscillation amplitude. Because of our trigger strategy, the Z (→ νν) + jets process overlaid by pileup events is the dominant background. We find that the ∼ 100 fb−1 dataset at the LHC will be able to probe the colored fermion (scalar) quirks with masses up to 2.1 (1.1) TeV and the color neutral fermion (scalar) quirks with masses up to 450 (150) GeV, respectively.
A
bstract
We analyze the observational potential of single
t
′
production in both the
t
′
→
bW
and
t
′
→
th
decay channels at 8 TeV LHC using an integrated luminosity of 25 fb
−1
. Our analysis is ...based on a simplified model with minimal coset SO(5)
/
SO(4) in which the
t
′
is a singlet of the unbroken SO(4). The single
t
′
production, as a consequence of electroweak symmetry breaking, is less kinematically suppressed, associated with a light forward jet and has boosted decay products at the 8 TeV LHC. Therefore it provides the most promising channel in searching for a heavy
t
′
. We have exploited the above kinematical features and used the jet substructure method to reconstruct the boosted Higgs in
th
decay channel. It is shown that a strong constraint on the
t
′
bW
coupling (
g
t
′
bW
/g
tbW,SM
<
0
.
2 ~ 0
.
3) at the 95% C. L. can be obtained for
m
t′
⊂ (700
,
1000) GeV.
The extended Higgs sector, such as by a second Higgs doublet of type II, provides portals to the dark sector which contain missing particles at the LHC, e.g., dark matter particles. In this paper, ...working in the simplified model and taking into consideration the wide decay-width effect of the mediator, we analyze the characteristic signatures of mono-b+MET and 2b+MET at the LHC. The latter signature was believed to be ineffective, while we found that, with the aid of razor shape analysis, it should be as important as the mono-b signature. In the region of relatively low mediator mass (below a few hundred GeV), by requiring a signal-to-background ratio greater than a few percent, the 2b-tagged razor analysis has comparable sensitivity to the mono-b search; it is even better for a mediator lighter than ∼200 GeV.
We study the LHC searches for the heavy CP-odd Higgs boson A and CP-even Higgs boson H in the context of a general two-Higgs-doublet model. Specifically, we consider the decay mode of A/Harrowrighttt ...through the tt associated production channels. In the so-called "alignment limit" of the two-Higgs-doublet model, this decay mode can be the most dominant one. By employing the HEPTopTagger and the multivariate analysis method, we present the search sensitivities for both CP-odd Higgs boson A and CP-even Higgs boson H via this channel with multiple top quarks at the high-luminosity LHC runs.
A
bstract
Some interpretations of
R
D
∗
anomaly in
B
meson decay using leptoquark (LQ) models can also generate top quark decays through Flavor Changing Neutral Current (FCNC). In this work we focus ...on two LQs, i.e. scalar
S
1
and vector
U
1
which are both singlet under the SU(2)
L
gauge group in the Standard Model (SM). We investigate their implications on the 3-body top FCNC decays
t
→
cℓ
i
ℓ
j
at tree level and the 2-body
t
→
cV
at one-loop level, with ℓ being the SM leptons and
V
=
γ, Z, g
being the SM gauge bosons. We utilize the 2
σ
parameter fitting ranges of the LQ models and find that
Br
(
t
→
cℓ
i
ℓ
j
) at tree level can reach
O
(10
−6
) and
Br
(
t
→
cV
) at one-loop level can reach
O
(10
−10
). Some quick collider search prospects are also analyzed.
The doubly charged Higgs bosons
H
±
±
searches at the large hadron collider (LHC) have been studied extensively and strong bound is available for
H
±
±
dominantly decaying into a pair of same-sign ...di-leptons. In this paper we point out that there is a large cavity in the light
H
±
±
mass region left unexcluded. In particular,
H
±
±
can dominantly decay into
WW
or
W
W
∗
(For instance, in the type-II seesaw mechanism the triplet acquires a vacuum expectation value around 1 GeV), and then it is found that
H
±
±
with mass even below
2
m
W
remains untouched by the current collider searches. Searching for such a
H
±
±
at the LHC is the topic of this paper. We perform detailed signal and background simulation, especially including the non-prompt
t
t
¯
background which is the dominant one nevertheless ignored before. We show that such
H
±
±
should be observable at the 14 TeV LHC with 10–30 fb
-
1
integrated luminosity.
The Higgs field in the standard model may couple to new physics sectors related to dark matter and/or massive neutrinos. In this Letter we propose a novel signature, the boosted di-Higgs-boson plus ...E_{T} (which is either a dark matter or neutrino), to probe those new physics sectors. In a large class of models, in particular, the supersymmetric standard models and low scale seesaw mechanisms, this signature can play a key role. The signature has a clear background, and at the sqrts=14 TeV high luminosity LHC, we can probe it with a production rate as low as ∼0.1 fb. We apply it to benchmark models, supersymmetry in the bino-Higgsino limit, the canonical seesaw model, and the little Higgs model, finding that the masses of the Higgsino, right-handed neutrino, and heavy vector boson can be probed up to ∼500, 650, and 900 GeV, respectively.
The search for singlet fermion dark matter at high-energy colliders is commonly analyzed with a singlet scalar mediator, which however violates the standard model (SM) gauge invariance, ...renormalizability and unitarity. These problems can be cured by introducing a mixing between the singlet scalar s and the SM Higgs boson h. Thus one has to consider two scalar mediators h1 and h2, where h1 is identified as the discovered 125 GeV Higgs boson. As a specific example, we consider the dark matter (DM) search in the tt¯+ET channel. According to the masses of dark matter and two scalar mediators, we classify the process into four cases. By investigating the total cross sections and differential distributions, we find that the contribution of the 125 GeV Higgs boson h1 cannot be neglected in all cases and can even dominate once h1 is on shell in dark matter production. Further, we study the impact of h1 on the LHC bounds of dark matter searches in the hadronic and semileptonic channels with the integrated luminosity of 36 fb−1. Finally we make a brief comment that h1 should be also considered in the vector DM search at high-energy colliders.
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