If you have questions or more information, please contact Doug.Wright@llnl.gov.
<hr>

<a href=lepc01.ps.gz>Talk by Higgs Working Group at LEP Physics Jamboree July 10, 2001 (ps)</a>

<hr>
Combined LEP claim of Higgs excess (Jul 01)
<pre>
hep-ex/0107029

Search for the Standard Model Higgs Boson at LEP

Authors: ALEPH,DELPHI, L3, OPAL, and the LEP Higgs Working Group
Report-no: LHWG Note/2001-03

The four LEP collaborations, ALEPH, DELPHI, L3 and OPAL, have
collected 2465 pb-1 of e+e- collision data at energies between 189 and
209 GeV, of which 542 pb-1 were collected above 206 GeV. Searches for
the Standard Model Higgs boson have been performed by each of the LEP
collaborations. Their data have been combined and examined for their
consistency with the Standard Model background and various Standard
Model Higgs boson mass hypotheses. A lower bound of 114.1 GeV has been
obtained at the 95% confidence level for the mass of the Higgs
boson. The likelihood analysis shows a preference for a Higgs boson
with a mass of 115.6 GeV. At this mass, the probability for the
background to generate the observed effect is 3.5%.
</pre>

<hr>
L3 and ALPEH have put out preprints (Nov 00) claiming an
"excess" of events in their higgs search....

<pre>
hep-ex/0011043 l3
hep-ex/0011045 aleph
</pre>

<hr>

<br>Date: Wed, 08 Nov 2000 10:40:26 -0800
<br>From: Harvey Newman <newman@hep.caltech.edu>
<br>Subject: Announcement of the End of LEP

<Br>Dear Colleagues,

<p> The CERN DG has decided to shut down LEP definitively, and to
submit this recommendation to the CERN Council. You may be interested
in the enclosed Press Release.

<p>   Physicists in the LEP experiments are continuing to discuss the
possibility of extending the run, to clarify the evidence for a Higgs
boson at approximately 115 GeV. Dismantling will not start
until the Council has approved DG Maini's recommendation.

<p> LEP had an illustrious eleven years. On to LHC, and great physics at CMS.
best regards,

<p>Harvey Newman

<br><a href=http://press.web.cern.ch/Press/Releases00/PR14.00ELEPstop.html>Press release on end to LEP (Nov. 8, 2000)</a>

<hr>
<a href=http://lephiggs.web.cern.ch/LEPHIGGS/talks/index.html>All LEPC Higgs Group Talks (since 1997)</a>

<hr>
<b>
<font size=+1 color=#ee0000>
LEP Experiments Committee, CERN Main Auditorium - 3 November, 2000.</b>
</font>
<p>
<ul>
<li>
"Status of the Higgs Search at Aleph." Peter McNamara, Univ. Wisconsin, ALEPH <br>
<a href="http://l3www.cern.ch/conferences/ps/Alephlepc_nov00.pdf"> Presentation (.pdf) </a> <br> <br>
<li>
"To be or not to be ... HIGGS-like ?" Pierre Lutz, Saclay, DELPHI. <br><a href="http://l3www.cern.ch/conferences/ps/PLutz_lepcNov3.ps.gz"> Presentation (.ps.gz) </a> <br> <br>
<li>
"Status of Higgs Search with L3" Marta Felcini. <br> <a href="http://l3www.cern.ch/conferences/ps/mfelcini_lepc.ps.gz"> Presentation (.ps.gz) </a> <br>
and <a href="//l3www.cern.ch/Protect/note/note-2620.ps.gz"> "Study of the L3 H nu nu Event" </a> New Note on L3 Higgs Search <br> <br>
</li>

<li>
"Results from the OPAL Experiment" Arnulf Quadt, CERN-EP, OPAL. <br> <a href="http://l3www.cern.ch/conferences/ps/AQuadt_LepcNov3.ps.gz"> Presentation (.ps.gz)</a> <br> <br>

LEP Higgs working groups Report : ALEPH, DELPHI, L3, OPAL and the LEP Higgs Working Group.
<li>
"Status of Higgs Boson Searches." Peter Igo-Kemenes, Heidelberg/CERN <br> <a href="http://l3www.cern.ch/conferences/ps/pik_LepcNov3_2000.ps.gz"> Presentation (ps.gz)</a> - 
- <a href="http://l3www.cern.ch/conferences/ps/pik_LepcNov3_2000.pdf"> Presentation (.pdf)</a><br>
<br>

</li></ul>

<hr><!-------------------------------------------------------------------------------------------------------->
<b>
<font size=+1 color=#ee0000>
CERN EP Seminar, Main Auditorium - 14 November, 2000.</b>
</font>
<p>
<ul>
<li>
"L3 Higgs Candidates" <br>
Christopher Tully, Princeton University <br>
<a href="http://l3www.cern.ch/conferences/ps/Tully_CERN00.pdf"> Presentation (.pdf) and 
<a href="http://l3www.cern.ch/conferences/ps/Tully_CERN00.ps.gz"> Presentation (.ps) </a> <br> 
</li></ul>
<BR>

<hr>
<a href=http://press.web.cern.ch/Press/Releases00/PR08.00ELEPRundelay.html>CERN press release: LEP run extended to Nov 2, 2000.</a>

<p> Quotations:
<ul><li>"a number of events compatible with a Higgs boson production with
mass around 114-115 GeV was reported in the combined results of the
four LEP experiments, ALEPH, DELPHI, L3 and OPAL.  However, the
topology of these events is also compatible with originating from
other known standard model processes."

<li>"The extension. the maximum still compatible with the tight LHC
construction schedule, will effectively double the
experimental data at centre-of-mass energy above 206 GeV."
</ul>
<hr>
Combined LEP result for 4-jet events: (page 13 of Higgs Working Group Talk to LEPC 9-5-00)

<p>If you only look at one plot, this is the one to look at: <a
href=lepc_sep5_00/higgs_wg_p13.ps>Plot.</a> 

<p>This plot compares the data with Monte Carlo prediction of the
background and Higgs signal assuming a 114 GeV Standard Model
Higgs. The data are shown three times with cuts tightened to give
Signal/Background of 0.3, 1.0, and 2.0. For the last case the result
is
<ul>
<li> 12 data events, 5 expected background and 2 expected Higgs events. 
</ul>
If one restricts the data to reconstructed masses above
110 GeV then there are 
<ul><li>7 data events, 2 expected background and 2 expected Higgs events.
</ul>
Recall that Fermilab claims that they can discover the Higgs in Run II
if the mass is less than 135 GeV.

<hr>
Presentations to LEPC (LEP Experiments Committee) Sept 5, 2000:
<ul>
<li><a href=lepc_sep5_00/higgs_wg.ps.gz>Higgs Working Group</a>
<li><a href=lepc_sep5_00/aleph.pdf>(1)Aleph</a>  see pages 8-26  
<li><a href=lepc_sep5_00/delphi.pdf>(2)Delphi</a> see pages 8-21
<li><a href=lepc_sep5_00/opal.ps.gz>(3)Opal</a> see pages 11-17
<li><a href=lepc_sep5_00/l3.ps.gz>(4)L3</a> see pages 4-9
</ul>

At the LEPC meeting, Aleph and Delphi claimed and excess,
L3 claimed no excess and Opal did not claim an excess (because
they don't have one).
<hr>
(1)Aleph Presentation to LEPC on Sept. 5, 2000. 

<p>Higgs evidence: pages 8-26. Pages 20, 25, and 26 contain the
gist of the evidence. 

<p>ALEPH tightens their cuts on the Standard Model Higgs search and
observes 3 events with an expected background of only 0.3. They only
expect 0.6 from the Higgs, so either they got lucky, the Higgs has a
larger cross-section than expected or this is a fluctuation in the
background. The signal events are also consistent with the hypothesis
that they come from ZZ events (i.e. background).

<p>All three signal candidates are four jet events.  LEP produces
Higgs by e+e- -> Z and the Z boson then radiates a Higgs so you have a
Z and Higgs final state.  The light Higgs would preferentially decay
to two b jets. The Z will decay to a pair of jets, or a pair of
leptons.  LEP is running at a center of mass energy of 206.5 GeV. So
if this is a Higgs, then it would have a mass of about 114 GeV.

<hr>
(2) Delphi Presentation to LEPC on Sept. 5, 2000. 
<p> Higgs evidence: pages 8-21. 
<p>Page 14 claim excess of 4-jet events with b-tag. 13 candidates expect 8.3 background and 1.8
Higgs events

<hr> Opal Presentation to LEPC on Sept. 5, 2000. 
<p> Higgs evidence: pages 11-17. Page 13 best summary of their evidence.

<hr>
(4) L3 Presentation to LEPC on Sept. 5, 2000. 
<p> Higgs evidence: Pages 4-9. Conclusion on page 14. Best?
Higgs candidates on Page 16 (qq nu nu event), Page 17 (4-jet event).

<hr>
<p>Report from Vuko Brigljevic (Sep. 5, 2000)
<ul>
<li>The 3 other LEP experiments do not see any excess.
<li>The LEP run has been extended until at least end
  of September (it should be finishing this week according
  to first plans).
<li> They are thinking about extensions until the end of the
  year (2000) but the decision is quite hard because:
<ul>
    <li> After October 1st, they will have to pay some 
       significant money for every delayed day: according
       to contracts made with construction companies, they
       were supposed to start then and the companies of course
       want their money.
    <li> it may delay LHC by a year.
</ul>
<li> The news about a possible Higgs signal came big in the 
  local (non-scientific) papers here, far exagerating what
  is really happening (as usual).
</ul>





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