11,927 research outputs found
\Lambda_b Lifetime from the HQET Sum Rule
The HQET sum rule analysis for the \Lambda_b matrix element of the four-quark
operator relevant to its lifetime is reported. Our main conclusion is that the
lifetime ratio \tau(\Lambda_b)/\tau(B^0) can be as low as 0.91.Comment: 5 pages, latex, no figures, uses sprocl.sty (included). Talk by C.
Liu at Int. Conf. on Flavor Phys., Zhang-Jia-Jie, 31/5-6/6 200
Pair production of 125 GeV Higgs boson in the SM extension with color-octet scalars at the LHC
Although the Higgs boson mass and single production rate have been determined
more or less precisely, its other properties may deviate significantly from its
predictions in the standard model (SM) due to the uncertainty of Higgs data. In
this work we study the Higgs pair production at the LHC in the Manohar-Wise
model, which extends the SM by one family of color-octet and isospin-doublet
scalars. We first scanned over the parameter space of the Manohar-Wise model
considering exprimental constraints and performed fits in the model to the
latest Higgs data by using the ATLAS and CMS data separately. Then we
calculated the Higgs pair production rate and investigated the potential of its
discovery at the LHC14. We conclude that: (i) Under current constrains
including Higgs data after Run I of the LHC, the cross section of Higgs pair
production in the Manohar-Wise model can be enhanced up to even times
prediction in the SM. (ii) Moreover, the sizable enhancement comes from the
contributions of the CP-odd color-octet scalar . For lighter scalar
and larger values of , the cross section of Higgs pair
production can be much larger. (iii) After running again of LHC at 14 TeV, most
of the parameter spaces in the Manohar-Wise model can be test. For an
integrated luminosity of 100 fb at the LHC14, when the normalized ratio
, the process of Higgs pair production can be detected.Comment: 13 pages, 4 figure
Exotic Higgs Decay at the LHeC
We study the exotic decay of the 125 GeV Higgs boson () into a pair of
light spin-0 particles () which subsequently decays and results in a
final state. This decay mode is well motivated in the Next to Minimal
Supersymmetric Standard Model (NMSSM) and extended Higgs sector models. Instead
of searching at the Large Hadron Collider (LHC) and the High Luminosity Large
Hadron Collider (HL-LHC) which are beset by large Standard Model (SM)
backgrounds, we investigate this decay channel at the much cleaner Large Hadron
Electron Collider (LHeC). With some simple selection cuts this channel becomes
nearly free of background at this machine, in stark contrast with the
situation at the (HL-)LHC. With a parton level analysis we show that for the
mass range , with luminosity the LHeC is
generally capable of constraining
( denotes the coupling strength relative to
the SM value) to a few percent level ( CLs). With luminosity
at a few per mille level can be probed. These sensitivities are much
better than the HL-LHC performance and demonstrate the important role expected
to be played by the LHeC in probing exotic Higgs decay processes, in addition
to the already proposed invisible Higgs decay channel.Comment: 10 pages, 5 figures. Version accepted by EPJC. Tables and figures
updated after correcting a mistake in signal event generation. Results
essentially unchange
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