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Good morning everybody, <br>
<br>
remember: the JYFL Colloquium soon today, at 10 in FYS1.<br>
<br>
Welcome!<br>
KJE<br>
<br>
<br>
On 28.4.2011 15:12, Kari J. Eskola wrote:
<blockquote cite="mid:4DB959B2.20502@phys.jyu.fi" type="cite">
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<font size="-1"><font face="Courier New, Courier, monospace">Dear
all, <br>
<br>
welcome to this week's JYFL Colloquium, Fri 29 April, at 10:15
in FYS1, and coffee at 10:00.<br>
<br>
Speaker: Lauri Wendland, Helsinki Institute of Physics<br>
<br>
Title: Status of Higgs Boson Searches in the CMS Experiment at
the CERN LHC<br>
<br>
Abstract:<br>
The breaking of the electroweak symmetry is the last
unconfirmed part of the standard model of particle physics,
which describes elementary particles and their interactions.
The spontaneous breaking of the electroweak symmetry is
assumed to account for the generation of masses of different
particles through the Higgs mechanism. The Higgs mechanism
requires, however, the existence of one or more Higgs bosons,
which so far have not been experimentally discovered. Since
the mass of the Higgs boson is limited by theoretical
constraints below the TeV energy scale, the LHC and its
general-purpose detectors, including the CMS experiment [1],
are, for the first time, in a position to either confirm or
exclude the existence of the Higgs boson.<br>
The current status of efforts for finding the Higgs boson at
the CMS experiment is discussed for both the standard model
(SM) and the minimal supersymmetric standard model (MSSM), the
currently most prominent theory to extend the standard model
to a more general theory. Results of the following four
different Higgs boson searches are presented [2-5]:<br>
<br>
• SM Higgs boson search in<br>
H --> W^+ W^− --> (ℓ^+ nu_ℓ) (ℓ^− nu_ℓ),<br>
• MSSM heavy neutral Higgs boson search in<br>
H/A --> tau^+ tau^− --> (e^± nu_e nu_tau ) (μ^∓
nu_μ nu_τ ) or (tau^±_hadr nu_τ )(ℓ^∓ nu_ℓ nu_tau ),<br>
• MSSM light charged Higgs bosons search in<br>
t tbar --> (b H^±) (bbar W^∓) --> (b tau^±
nu_tau )(bbar ℓ^∓ nu_ℓ) --> (b tau^±_hadr nu_tau nu_tau
)(bbar ℓ^∓nu_ℓ), and<br>
• doubly charged Higgs boson search in Higgs triplet models
via<br>
Z/gamma --> Φ^++ Φ^−− --> (ℓ^+ℓ^+) (ℓ^−ℓ^−) and W^±
--> Φ^++ Φ^− --> (ℓ^+ℓ^+)(ℓ^− nu_ℓ),<br>
<br>
where ℓ = e or μ and tau_hadr denotes hadronic tau decays. The
results are based on the 36 pb^−1 of data collected in 2010.
No excess of events has been observed over the SM backgrounds,
but sensitivity is found to be good enough to experimentally
narrow down the existing mass limits in some of the analyzed
decay channels. Therefore, the data to be collected during
2011 has already the potential to show first hints of the
elusive Higgs boson or to exclude its existence over a large
area of parameter space.<br>
References<br>
[1] The CMS Collaboration, “The CMS Experiment at the CERN
LHC”, JINST 3:S08004 (2008)<br>
[2] The CMS Collaboration, “Measurement of W+W− Production and
Search for the Higgs Boson in pp Collisions at ps=7 TeV”,
Phys. Lett. B 699 (2011) 25-47, arXiv:1102.5429<br>
[3] The CMS Collaboration, “Search for Neutral MSSM Higgs
Bosons Decaying to Tau Pairs in pp Collisions at ps=7 TeV”,
submitted to Phys.Rev.Lett., arXiv:1104.1619<br>
[4] The CMS Collaboration, “Search for the charged Higgs boson
in the etau and mutau dilepton channels of top quark pair
decays”, CMS-PAS-HIG-11-002<br>
[5] The CMS Collaboration, “Search four doubly charged Higgs
to charged leptons”, CMS-PAS-HIG-11-001<br>
<br>
See you all there!<br>
Kari Eskola and Ilari Maasilta<br>
<br>
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