Dear Chip, Michael and Ashutosh,
This looks reasonably OK within the confines of what has so far
been discussed, but I do
worry that not everybody will read it in the same informed spirit as
Ashutosh. I do agree with points a and b.
I would however counsel against the explicit mention of accelerator R&D.
The earlier wording about
"more concerted work on its design and physics capability" seems to me
to strike the right tone.
We should also all realize that current US accelerator R&D is already
funding
LARP, high-field magnets, MAP, but has cut back/zeroed out high-gradient
super-conducting RF (ILC) and put on life-support other parts of the ILC
R&D program.
Getting the best science out of ILC will need US accelerator development
efforts.
regards
Graham
On 8/24/2013 4:17 PM, Ashutosh Kotwal wrote:
> hi,
> Looks fine to me.
>
> I think the language regarding the 100 TeV pp machine makes it clear
> that we are just interested in further studies for the longer term,
> not at the expense of really important programs which will occupy us
> in the next 20 years.
>
> It is also not rhetorical because times have changed since the last
> discussion from 10 years ago.
> a) the LHC is no longer in the future, it is the running machine.
> 10 years ago, the Tevatron run 2 was just starting and LHC was X years
> away. The VLHC could have looked like the Next-to-next pp machine and
> sounded to some like "we are getting ahead of ourselves". But now,
> the future is closer.
> b) The Higgs is found, AND it is close to the SM predicted mass.
> This tells us, 100 TeV may not be overkill. We should have a plan for
> getting to that energy scale. This is new information compared to 10
> years ago.
>
> SSC and LHC discussions started 30 years ago. Snowmass is the
> place to think 30 years ahead. To me, an interest in this R&D plan
> does not appear competitive or alternative to HL-LHC or ILC.
>
> regards,
> Ashutosh
>
>
> On Aug 24, 2013, at 3:04 PM, Raymond Brock <[log in to unmask]
> <mailto:[log in to unmask]>> wrote:
>
>> hi everyone,
>>
>> As you can imagine, we're fighting length and nuance. We apologize if
>> we went too far in shortening and then going below what you suggested
>> as the threshold for the VLHC. We've gone back and forth about
>> calling out the muon collider explicitly, and decided against it but
>> we've tried to come up with an approach to take Cecilia's valid
>> concerns into account.
>>
>> My personal concern is that there is always an overall fascination
>> with higher energy. Remember, I have been a proponent and lost
>> that battle years ago. But I would hate for Snowmass to _appear_ to
>> have suddenly fallen in love over 9 days with this old flame at the
>> expense of really important and hair-on-fire programs that we already
>> cannot support. And I don't think that's where you guys are. So it's
>> tricky rhetorical spot, right? We've tried to take into account
>> comments that have come in from Liantao, Meena, Rick, Graham,
>> Ashutosh, Tom, Markus, and Ron. Here is where it stands now.
>>
>> We have to complete this and Michael and I will try to talk about 8pm
>> EDT this evening. So please have your (final?) reactions to us by
>> about 6pm EDT?
>>
>> thanks
>> Michael and Chip
>>
>> Here we go:
>>
>> Energy Frontier. The mysteries of the newly discovered Higgs boson
>> were a major theme at Snowmass. The properties of the Higgs
>> boson raise crucial questions that guide large parts of the future
>> particle physics program. Indeed, this discovery changes everything.
>> It calls for a three-pronged research program at high energy
>> accelerators: first, to determine the properties of the Higgs boson
>> as accurately as possible, second, to make precise measurements of
>> the heavy particles $W$, $Z$, and the top quark, which can carry the
>> imprint of the Higgs field; and, third, to search for new particles
>> predicted by models of the Higgs boson and electroweak symmetry
>> breaking. These questions also drive experiments in other frontiers.
>> The expectation of TeV scale particles directly motivates the search
>> for WIMP Dark Matter and flavor changing rare decays.
>>
>> For at least the next fifteen years, the experiments at the Large
>> Hadron Collider at CERN will drive the Energy Frontier program
>> forward. The Higgs boson discovery at the LHC now becomes a precision
>> study of the properties of this particle. The high-luminosity LHC
>> will measure Higgs boson couplings at the few-percent level and
>> provide the first measurement of the Higgs self-coupling. The steps
>> of the LHC to 300 fb$^{-1}$ and then to 3000 fb$^{-1} will explore
>> deeply for new particles produced through either the strong or the
>> electroweak interactions. They will probe for new dynamics of $W$,
>> $Z$, and Higgs at TeV energies and study rare decays using a sample
>> of billions of top quarks. The LHC experiments have already proven
>> their ability to work as global collaborations. US contributions to
>> the leadership, detector and accelerator components, technology, and
>> physics insight have played indispensable roles.
>>
>> There is compelling scientific motivation for continuing this program
>> with lepton colliders. Experiments at these accelerators can reach
>> sub-percent precision in the Higgs boson properties in
>> a unique, model-independent way, enabling discovery of percent-level
>> deviations predicted in theoretical models. They can improve the
>> precision of our knowledge of the $W$, $Z$, and top properties by an
>> order of magnitude, allowing the discovery of predicted new physics
>> effects. They search for new particles with unequivocal discovery or
>> exclusion, complementing new particle searches at the LHC. A global
>> effort has now completed the technical design of the International
>> Linear Collider (ILC) accelerator and detectors that will provide
>> these capabilities. The Japanese high energy physics community has
>> named this facility as its first priority.
>>
>> The Snowmass study considered many other options for high-energy
>> colliders that might be realized over a longer term. These
>> included higher energy linear colliders, circular e+e- colliders,
>> muon colliders, and photon colliders and all merit continued study.
>> The Snowmass study called out in particular the potential of a 100
>> TeV hadron collider. While higher energy per se is always an
>> advantage, this threshold seems to reach benchmarks suggested by
>> questions about dark matter and naturalness. Our conclusions call
>> for renewed accelerator R&D and physics studies for such a
>> machine over the next decade.
>>
>> In all of the projects listed above, US leadership in developing
>> experimental and accelerator technology is playing a critical role.
>> These US initiatives are essential to meet the world-wide scientific
>> goals in particle physics.
>>
>> ---------------------------------------------------------------
>> 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] <mailto:[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/ <http://www.pa.msu.edu/%7Ebrock/>
>> 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
>>
>>
>>
>>
>>
>>
>>
>>
>>
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--
Graham W. Wilson
Associate Professor
Dept. of Physics and Astronomy
University of Kansas
Lawrence, KS 66045
Office Tel. 785-864-5231
Web: http://heplx3.phsx.ku.edu/~graham/
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