Hi Graham,
The 8% precision on the Higgs self-coupling from VLHC comes from white paper submitted
by Wei-Ming Yao and this analysis reproduces the results for HL-LHC and extends the analysis
to HE-LHC and VLHC. Jianming is away, but knows the status of the documentation for that
analysis (which I gather you have not seen).
It is true that there is another potential source for higher precision on the Higgs self-coupling.
The 6 TeV muon collider has the potential to achieve 2% and if this white paper contribution
arrives in time with the full background simulation, then we will revise that conclusion point.
Best,
Chris
On Aug 23, 2013, at 12:11 PM, Graham W. Wilson <[log in to unmask]> wrote:
> Hi Rick,
>
> I haven't followed the hadron collider Higgs self-coupling discussion in detail, but from a quick reading of the
> draft Higgs report and relevant papers (I couldn't find ref 69), it seems clear that double-Higgs production statistics
> is likely to be a strength of VLHC. But how much this translates into a Higgs self coupling measurement
> and in particular a model-independent measurement of the Higgs self-coupling when there is a 30% error on
> the theoretical cross-section and many different non HHH coupling contributions to final states with HH is not clear at all.
> So I don't think your "likely the best place for Higgs self-coupling" is supported by the current documentation.
>
> regards
> Graham
>
> On 8/23/2013 9:45 AM, Rick Van Kooten wrote:
>> On 8/22/13 8:57 PM, Peskin, Michael E. wrote:
>>>
>>> Dear Colleagues,
>>>
>>> I attach the most recent versions of the Snowmass Executive Summary and the
>>> EF 5-page summary. We will discuss these in our meeting tomorrow.
>>>
>>> The Executive summary got somewhat rearranged. The frontier conveners
>>> wanted the capabilities sections pulled out and merged into a common section.
>>> This means that the accelerator part of the LHC, ILC, and VLHC discussion
>>> occurs much later in the document. But, please look it over. I did insert
>>> language on the US leadership in high-field magnets.
>>
>> Regarding the current top-level executive summary, I would like to see the _unique_ capabilities of e+e- machines stressed, and as one example:
>>
>> "They can reach sub-percent precision in the Higgs boson properties, allowing discoveries of percent-level deviations predicted in theoretical models."
>>
>> to
>>
>> "They can reach sub-percent precision in the Higgs boson properties in a unique, model-independent way, allowing discoveries of percent-level deviations predicted in theoretical models."
>>
>> This is just transferring some wording from the longer summary. I believe that we are all agreed that an "all hadron" option, i.e., HL-LHC -> HE-LHC/VLHC would definitely be missing out on important physics and capabilities and we want to make that clear.
>>
>> Also a small suggestion: adding "at least", i.e.,:
>>
>> "They can improve the precision of our knowledge of the $W$, $Z$, and top properties by at least an order of magnitude".
>>
>>>
>>> As to the rest of the VLHC discussion, let's talk about it tomorrow. The
>>> new particles group would like a stronger endorsement of VLHC in the executive
>>> summary. I am rather cool to this, because the VLHC is not on the table
>>> now. It would be good to get more opinions from the members of
>>> our group.
>>
>> There is no denying that a ~100 TeV VLHC brings a lot to the table (including likely the best place for Higgs self-coupling) and we should say this, but with the caveats that Graham clearly points out. I do like Ashutosh's suggested wording encouraging a conceptual design report which is what would be needed to come to more solid conclusion. We could preface his encouraging statement with "Although beyond the 20-year timeline of this report, further investigations of the physics and technical issues would be opportune at this time..." (and indeed the same holds true for TLEP).
>>
>> Regards,
>> Rick
>>
>>
>
>
> --
> 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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