Hi Chip,

Question: Did any of you hear any substantive suggestion that a VLHC should be the follow-on collider to LHC? I'm asking for a reason...the mention of ILC in this way is deemed as not representative of the whole community and as "there are also those who believe in that a 100 TeV proton machine should be next" (a quote from a prominent fellow).

there was a colloquium at Snowmass given by Markus on the need for 100 TeV machine, and
at least part of the community is quite excited about it.
Following Nima's argument, 100 TeV is a machine that can be used to discover that we live in a 
fine-tuned world (10^-4 or so).

-y


I personally don't think that 100% unanimity is required in order to emphasize one future program over others. But I'd really not heard this particular sentiment in any substantive way.

best
Chip

On Aug 17, 2013, at 4:19 PM, Tom LeCompte <[log in to unmask]> wrote:

Hi Michael,

I am not sure Line 119 says what we want it to say: " Experiments at lepton colliders allow unambiguous searches for new particles...".  I don't think you mean the searches themselves are unambiguous (and by extension, that the searches at the LHC are ambiguous).  Maybe you mean that the *interpretations* are unambiguous (or at least clearer) than at hadron colliders.

See you Thursday,

Tom


On 8/17/2013 5:35 PM, Peskin, Michael E. wrote:
[log in to unmask]" type="cite">
Dear Colleagues,

Chip and I have been presenting at the DPF meeting and trying to catch up on our sleep.
However, the work for Snowmass is not yet done.  We have some important questions 
for you.

I attach a draft of the highest-level Executive Summary of Snowmass.   This is in a very 
preliminary state; please do not circulate it further.   Chip and I ask in particular whether
you are in agreement with the 3-paragraphs that relate specifically to Energy Frontier.
I attach these at the end of this note.    This document is under revision now, so please
send your reactions as soon as possible. 

The executive summary will be the first part of a 30-page Snowmass summary document.
That will include a 4-5 page summary of the results of the Energy Frontier study.  Chip and I 
are working on our final revisions of a first draft.  We will circulate that to this list tomorrow.

The 30-page summary of Energy Frontier is not yet ready to be circulated. We are sorry for the
delay.  However, this document will follow closely the long version of Chip's talk given on Sunday
at Snowmass.  We just need to put this into prose.

We would like to return to our scheduled phone meeting of the EF conveners this week and
next week.  I remind you that time is 11am PDT/ 2pm EDT Thursday, and that the coordinates are:

August 22: 11:00 PDT / 2:00 EDT
    Contact information:

 You call:    domestic...     (877) 873-8018
               international...    (636) 651-3182

  participant code: 290-043   

We will start the meeting promptly and end promptly after 1 hour.

The agenda for this week is discussion of the two summary documents.

I hope that your working group reports are headed toward completion by the end of the month.
I promised written comments on the drafts, but -- please excuse me -- I did not send these yet.
Please expect them early this week. 

Chip and I would like to thank you again for all of the work that you have put in thus far. Chip 
received much positive feedback on his talk at Snowmass, but, of course, the supporting work
is yours.  We are grateful.

Best wishes,

Michael 

--------------------------------------------------------------------------------------


EF paragraphs in the Snowmass executive summary
(In the full document, you will see that this is followed by paragraphs from the accelerator side)


The mysteries of the newly discovered Higgs boson were a major theme at Snowmass.  Much attention was given to the importance of studying the Higgs boson as closely as possible.  At high energy accelerators, the “Energy Frontier,” there are three approaches:  first, to search for new particles with TeV masses predicted by models of electroweak symmetry breaking, second, to make precise measurements of the heavy particles $W$, $Z$, and the top quark, which can carry the imprint of the Higgs, and, third, to measure the properties of the Higgs boson itself to very high precision.  This program is closely connected to the search for the dark matter particle and for flavor-changing rare decays; in both cases, the motivating theory is often associated with the Higgs and its symmetry-breaking.

For at least the next fifteen years, the experiments at the Large Hadron Collider at CERN will drive this program forward.  Especially in its high-luminosity phase, the LHC is expected to explore deeply for new particles produced through either the strong or the electroweak interactions.  They LHC will study rare decays using a sample of billions of top quarks, probe for new dynamics of W, Z, and Higgs at TeV energies.  It will measure Higgs boson couplings at the few-percent level and provide the first measurement of the Higgs self-coupling.  The LHC experiments have already proved their ability to work as global collaborations.  Technology, insights, and leadership from the US have played important roles in these experiments.

There is strong scientific motivation for continuing this program with lepton colliders. Experiments at lepton colliders allow unambiguous searches for new particles that complement those at the LHC. They can improve our precision knowledge of W, Z, and top by an order of magnitude, potentially bringing these measurements into confrontation with theory. They can reach sub-percent precision in the Higgs boson properties, allowing discoveries of percent-level deviations predicted in theoretical models. A global effort has now completed the technical design of the International Linear Collider (ILC), an accelerator that will give these capabilities.  The Japanese high energy physics community has named this facility as its first priority.


-------------------------------------------------------------------------------------------
  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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---------------------------------------------------------------
Raymond Brock  *  University Distinguished Professor
Department of Physics and Astronomy
Michigan State University
Biomedical Physical Sciences
567 WIlson Road, Room 3210
East Lansing, MI  48824
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cell: (517)927-5447
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