14,091 research outputs found
Four Jets as a Probe of O(100 GeV) Physics beyond Standard Model at Hadron Colliders
O(100 GeV) physics beyond the standard model (BSM) could be overlooked
provided that it is hidden in the untouched Higgs sector or jets. The top quark
forward-backward asymmetry measurements and di-jet bump, which is observed in
the associated production with charged lepton plus missing energy (supposed
arising from W decay), may indicate the existence of a new color-octet
axial-vector Z_C with a mass about 145 GeV. Here Z_C only decays into two jets.
In this paper we investigated the possibility to discover Z_C pair via
analyzing the four jets as the final states, which are heavily polluted by huge
QCD background. Our simulation showed that, however, both Tevatron and LHC have
the excellent chance to discover Z_C through analyzing the four jets events in
the current accumulated data.Comment: 15 pages, 11figures and 2 table
Deci-weak at Tevatron and LHC
Recently Tevatron released their measurements on invariant mass spectrum of
electron/positron, as well as the di-jet arising from WW+WZ production with one
W leptonically decay. Though the statistics is not significant, there are two
bumps around 240 GeV and 120-160 GeV respectively. We proposed that the two
bumps correspond to the extra light gauge bosons and ,
which couple with quarks with the deci-weak strength. In this brief report, we
also simulated di-jet invariant mass distribution at the current running LHC.Comment: 8 pages, 3 EPS figures, ref added, figures update
Chandra Observation of a Weak Shock in the Galaxy Cluster A2556
Based on a 21.5 ks \chandra\ observation of A2556, we identify an edge on the
surface brightness profile (SBP) at about 160 kpc northeast of the
cluster center, and it corresponds to a shock front whose Mach number
is calculated to be . No prominent
substructure, such as sub-cluster, is found in either optical or X-ray band
that can be associated with the edge, suggesting that the conventional
super-sonic motion mechanism may not work in this case. As an alternative
solution, we propose that the nonlinear steepening of acoustic wave, which is
induced by the turbulence of the ICM at the core of the cluster, can be used to
explain the origin of the shock front. Although nonlinear steepening weak shock
is expected to occur frequently in clusters, why it is rarely observed still
remains a question that requires further investigation, including both deeper
X-ray observation and extensive theoretical studies.Comment: 15 pages, 4 figures, accepted by Ap
New Color-Octet Vector Boson Revisit
Motivated by CDF recent measurements on di-jet invariant mass spectrum where
di-jet is associated production with charged leptons () and missing
energy, we re-examine the previous proposed massive color-octet
axial-vector-like boson . Our simulation showed that the di-jet bump
around 120-160 GeV can be induced by with effective coupling (q represents the quark other than top and is the
strong coupling constant). Moreover our numerical investigation indicated that
the top quark forward-backward asymmetry can be reproduced without
distorting shape of differential cross section ,
provided that the and top quark coupling is appropriately chosen (). Our results also showed that the
theoretical as functions of and can be
consistent with data within and respectively.Comment: 8 pages, 3 EPS figure
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