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I do not feel that the exclusive emphasis on a lepton collider in the summary as the next step in the energy frontier accurately reflects the consensus in our field. There is tremendous enthusiasm for a 100 TeV pp collider (VLHC), strongly motivated by considerations of naturalness and dark matter in light of the Higgs discovery. I got many enthusiastic comments about my colloquium, which was an attempt to give a balanced comparison between the ILC and VLHC. They are very different machines with different strengths and different loopholes, and there is tremendous enthusiasm for both options. I got strongly positive feedback on my colloquium from both the linear collider community, as well as people enthusiastic about the VLHC. Unfortunately, I am not aware of anywhere else in Snowmass where the two collider options were compared head to head. Another piece of "data" on the views of the community is the input we got to the Snowmass NP report. Many people did "Snowmass only" work to study VLHC machines. Of course, these studies are not anywhere near the level of detail of the ILC studies, but they do reflect the level of enthusiasm in the field. My sense is that this enthusiasm for VLHC is starting to build in both the theory and experimental community. There will not be a Snowmass document for another decade, and a lot can happen in that time. To name just one possibility, China may decide to commit resources to build a VLHC. Any such project anywhere would need US participation to succeed. I believe it is imperative that the high-level Snowmass summary include a statement that VLHC also represents an exciting possibility for the next step forward. Markus Luty ============================================ Physics Department University of California, Davis One Shields Avenue Davis, CA 95616 Phone: +1 530 554 1280 Skype: markus_luty On Mon, Aug 19, 2013 at 9:13 AM, Raymond Brock <[log in to unmask]> wrote: > Hi > Yes, of course. What I was aiming at with my question about 100 TeV is > whether the selection from the executive summary that Michael sent you > missed the mark. Chris has suggested adding a sentence about other machines > having been considered. But the "center of gravity" in the second > paragraph regarding science at new machines would still be the ILC. > > Is this okay with you all? I personally think it's appropriate given all > of the current situation and the TDR-ness of ILC. > > best > Chip > > On Aug 19, 2013, at 7:15 AM, Yuri Gershtein < > [log in to unmask]> > wrote: > > 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: > > 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/ > --------------------------------------------------------------------------------------------- > ######################################################################## > Use REPLY-ALL to reply to list > > To unsubscribe from the SNOWMASS-EF list, click the following link:https://listserv.slac.stanford.edu/cgi-bin/wa?SUBED1=SNOWMASS-EF&A=1 > > > > ------------------------------ > > Use REPLY-ALL to reply to list > > To unsubscribe from the SNOWMASS-EF list, click the following link: > https://listserv.slac.stanford.edu/cgi-bin/wa?SUBED1=SNOWMASS-EF&A=1 > > > --------------------------------------------------------------- > 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 > sent from: [log in to unmask] > > cell: (517)927-5447 > MSU office: (517)353-1693/884-5579 > open fax: (517)355-6661 > secure fax: (517)351-0688 > Fermilab office: (630)840-2286 > CERN Office: 32 2-B03 * 76-71756 > > Twitter: @chipbrock > Home: http://www.pa.msu.edu/~brock/ > ISP220: http://www.pa.msu.edu/courses/ISP220/ > ISP213H: http://www.pa.msu.edu/courses/2007spring/ISP213H/ > Facebook: http://msu.facebook.com/profile.php?id=2312233 > > > > > > > > > > ------------------------------ > > Use REPLY-ALL to reply to list > > To unsubscribe from the SNOWMASS-EF list, click the following link: > https://listserv.slac.stanford.edu/cgi-bin/wa?SUBED1=SNOWMASS-EF&A=1 > > > > --------------------------------------------------------------- > 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 > sent from: [log in to unmask] > > cell: (517)927-5447 > MSU office: (517)353-1693/884-5579 > open fax: (517)355-6661 > secure fax: (517)351-0688 > Fermilab office: (630)840-2286 > CERN Office: 32 2-B03 * 76-71756 > > Twitter: @chipbrock > Home: http://www.pa.msu.edu/~brock/ > ISP220: http://www.pa.msu.edu/courses/ISP220/ > ISP213H: http://www.pa.msu.edu/courses/2007spring/ISP213H/ > Facebook: http://msu.facebook.com/profile.php?id=2312233 > > > > > > > > > > ------------------------------ > > Use REPLY-ALL to reply to list > > To unsubscribe from the SNOWMASS-EF list, click the following link: > https://listserv.slac.stanford.edu/cgi-bin/wa?SUBED1=SNOWMASS-EF&A=1 > ######################################################################## Use REPLY-ALL to reply to list To unsubscribe from the SNOWMASS-EF list, click the following link: https://listserv.slac.stanford.edu/cgi-bin/wa?SUBED1=SNOWMASS-EF&A=1