Minutes of the Energy Frontier conveners' meeting June 6, 2013
attending: Michael, Chip, Andy White, Heather, Lian-Tao, Sally Dawson, Meenakshi,
Jianming, Andrei Gritsan, Kaustubh, Ashutosh, Eric Torrence, Chris Tully, Yuri
-1. Michael circulated the note that Chip and Michael sent to the ATLAS, CMS, and LHCb collaborations. Chip has been worried that the ATLAS white paper process was not going to converge in time for Snowmass. After much discussion with members of ATLAS and CMS, we have outlined a process for getting the main conclusions understood in a timely fashion and then refining the quantitative conclusions of the working groups as information is made public by the collaborations. Please read this note carefully.
0. There will be a Physics Slam at the Minnesota meeting, on Friday evening, August 2. Marge Bardeen has asked for names of participants. Please volunteer, and suggest people from your group, especially young people. We want the Higgs boson and our other great stuff front and center in this competition.
1. Attendance at the Seattle meeting will be lower than we had hoped. However, there are people who are scheduled to speak who still have not registered. Gordon Watts would very much appreciate it if people who will be in Seattle in person would register soon. Also, please send to Chip and Michael a list of your group members who will be attending remotely. This list will apparently include a large group of people (~40) at CERN.
2. We discussed the status of the various groups vis-a-vis Seattle. You have received reports in writing from all groups except Flavor. Michael is especially pleased that the Higgs group has heard from ILC, CLIC, TLEP, and CMS and seems to have the comparison of Higgs capabilities for these facilities somewhat under control.
3. Over the next few weeks, we need to outline what we will present on the first day at Seattle. Ideally, the talks from the working groups on the first day would fit together into a set of physics cases for future EF facilities. We started discussing that today with one of the thornier points: What is the physics case for going from 300 fb-1 to 3000 fb-1 with the 14 TeV LHC? Michael had circulated a list of topics to be emphasized, which we added to by email and in our discussion at this meeting. The current list is appended below. Please feel free to extend it further, and please pick up these points as you prepare your talks for Seattle.
Best wishes,
Michael
==============================================================================
Elements of the case for 3000 fb-1:
1. Higgs:
Higgs mass from gamma gamma and ZZ*
general expectations for Higgs branching ratios
Very accurate, low systematics measurements, e.g.
Gamma(gamma gamma)/Gamma(ZZ*)
Rare SM branching fractions (mu mu, Z gamma)
Exotic branching fractions (invisible, e mu, mu tau, … )
Higgs pair production and nonlinear Higgs coupling
searches for additional Higgs particles, especially in
H -> ZZ, h + h, H, A -> tau tau H,A -> mu mu
closing of "the wedge"
2. W, Z physics:
Light Higgs "resolves" the unitarity problem, but still there
can be W,Z resonances in the TeV region. These are searched for
in vector boson scattering (directly) and studies of
3-vector couplings (indirectly)
3. Precision measurement:
Are there special strategies for mW, mt, alphas that can take advantage of
very high statistics by selecting special classes of events?
Improvement in parton distributions, especially in gluon and antiquark
distributions (w implications for mW, mt)
4. New particle searches:
The ancient wisdom is: a factor of 10 in luminosity gives a factor of 2
in energy . This fails to be true when the current limits are
already accessing the tails of parton distributions.
But certain searches can take full advantage of the improvement in
luminosity:
electroweakino searches in SUSY
searches for Drell-Yan resonances
searches for t tbar resonances, and for di-top or 4-top final states
searches involving long-lived lepton partners
mono-jet, mono-photon
extended Higgs processes above, and A,H -> ttbar
Some people would argue that no discovery at LHC with 3000 fb-1 excludes
"naturalness". Do we have an attitude toward this question?
5. Followup to discovery:
The opportunity for new particle discovery at LHC 300 fb-1 is high. What
measurements will then be needed?
clarification of decay patterns -- look at the pMSSM benchmark points
for examples of complex decays. More new particles will appear
if BR's are pushed to lower levels
rare leptonic and multilepton decay paths
new mechanisms for Higgs production from pp -> XXbar -> h + anything
tests of flavor-degenerate spectrum or flavor-changing decays
anomaly in W,Z: what is the tensor structure ? look in ZZ and other
complementary channels ( including Zh)
=============================================================================
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Michael E. Peskin [log in to unmask]
HEP Theory Group, MS 81 -------
SLAC National Accelerator Lab. phone: 1-(650)-926-3250
2575 Sand Hill Road fax: 1-(650)-926-2525
Menlo Park, CA 94025 USA www.slac.stanford.edu/~mpeskin/
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