It's easy to construct models where a 1 TeV Higgs wouldn't be seen at the
LHC
because its couplings to ordinary matter are too small. Take the Higgs
singlet
model: The couplings of the SM Higgs go like cos^2 of an angle, the
couplings
of the heavier Higgs go like sin^2 of the same angle.
I believe we need to emphasize the importance of exploring the TeV scale.
No matter what we see or don't see, we've learned something.
On Fri, Oct 11, 2013 at 3:26 PM, Raymond Brock <[log in to unmask]> wrote:
> Hi
> I too like what Markus has done. The broader argument in favor of TeV
> scale particles is the right one to make. I might make some few syntactical
> suggestions, but I'm missing something in the \emph lines. They say:
>
> To summarize: \emph{Compelling ideas about fundamental physics predict
> new
> particles at the TeV energy scale that are potentially accessible to
> present and
> planned future accelerators. These experiments are the crucial tests of
> these ideas.
> Furthermore, if such particles are discovered, they can be studied in
> detail to
> determine their properties, leading to the establishment of new
> fundamental laws of
> nature.}
>
> If there are new particles at the TeV scale predicted by these
> compelling ideas...then I would argue that it's more than just potentially
> that they're accessible at present and planned future accelerators. I
> understood the caution before, but the words were not so specific. I would
> say that if there are particles at the TeV scale...we'll find them.
>
> What am I missing? What would make them be at the TeV scale...and yet
> still invisible at LHC, ILC, VLHC?
>
> thanks
> Chip
>
>
> On Oct 11, 2013, at 1:57 AM, Markus A. Luty <[log in to unmask]>
> wrote:
>
> The first installment of my homework: here is my suggestion for what is
> now lines 31-41 of the 5-page summary. It is longer than what is there now,
> but I think these may be the most important lines in the document.
>
> The discovery of the Higgs particle establishes that the masses of
> elementary
> particles arise dominantly from interactions with the Higgs field that is
> turned
> on throughout the universe. We now have for the first time in the history
> of
> particle physics a theory all of whose ingredients have been experimentally
> verified, and that can be consistently extrapolated to energy scales many
> orders
> of magnitude above the energy scale of collider experiments. This historic
> achievement is not an end, but a beginning, because the standard model of
> particle physics leaves many fundamental questions unanswered. In the
> tradition
> of bold theoretical ideas such as the Higgs mechanism (recognized by this
> years'
> Nobel prize) particle physicists have proposed compelling ideas that
> address
> these important questions, and that have their crucial test at the TeV
> scale:
>
> * The fact that the observed Higgs particle is a scalar particle makes it
> very
> difficult to understand why its mass scale is smaller than much-larger
> fundamental mass scales such as the Planck scale. Addressing this problem
> requires significant additional structure: either supersymmetry (an
> extension of
> Einstein's spacetime symmetry), Higgs compositeness, or extra dimensions
> of
> space. All of these ideas predict a rich spectrum of particles at the TeV
> mass scale,
> typically including a larger Higgs sector.
>
> * The standard model does not account for the dark matter that makes up
> most of
> the matter of the universe. A stable particle at the Higgs mass scale with
> weak
> interactions with ordinary matter (a WIMP) is one of the simplest and
> compelling
> theories of dark matter. If dark matter is a WIMP it may be possible to
> study
> dark matter under controlled laboratory conditions in collider experiments.
>
> To summarize: \emph{Compelling ideas about fundamental physics predict new
> particles at the TeV energy scale that are potentially accessible to
> present and
> planned future accelerators. These experiments are the crucial tests of
> these ideas.
> Furthermore, if such particles are discovered, they can be studied in
> detail to
> determine their properties, leading to the establishment of new
> fundamental laws of
> nature.}
>
> The past successes of particle physics clearly call for us to continue and
> extend a three-pronged program of research in collider experiments:
>
> First, we must study the Higgs boson itself in as much detail as possible,
> searching for signs of a larger Higgs sector and the effects of new heavy
> particles.
>
> Second, we must search for small deviations in the standard model
> predictions
> for the couplings of the Higgs, W, Z, and top quark from new particles.
>
> Finally, we must directly search for new particles with TeV masses that can
> address important problems in fundamental physics.
>
> Markus Luty
>
> ============================================
> Physics Department
> University of California, Davis
> One Shields Avenue
> Davis, CA 95616
>
> Phone: +1 530 554 1280
> Skype: markus_luty
>
>
>
> On Thu, Oct 10, 2013 at 1:57 PM, Ashutosh Kotwal <[log in to unmask]>wrote:
>
>> On Oct 10, 2013, at 4:03 PM, "Peskin, Michael E." <
>> [log in to unmask]> wrote:
>>
>> > minutes of the EF phone meeting 10/8
>> >
>> > attending: Chip, Michael, Sally, Daniel, LianTao, Ashutosh, Cecilia,
>> Reinhard, Markus, Andy White
>> >
>> > There are many items in these minutes that all of you need act on more
>> or less immediately. Please read these minutes carefully. We summary the
>> action items at the end.
>> >
>> > Our reports are overdue. We would like to send our reports to the
>> Snowmass conveners on Tuesday, October 15.
>> >
>> > All line numbers refer to the 10-3 versions sent out last Friday.
>> >
>> > 1. From the group on the phone, and from the emails that we have
>> received, you seem to be happy with the reports that we put together except
>> for some specific points discussed below. Michael emphasized that, if you
>> are not happy, you must speak up now. This is best done by sending email
>> to snowmass-ef. Urgently, please.
>> >
>> > 2. Many of the people on the phone were uncomfortable with the
>> language on likes 40-41 of the short report: "These puzzles imply that new
>> particles with masses of the order of 1 TeV which resolve these questions
>> will be found -- and will be accessible to existing and planned
>> accelerators." They felt that "imply" was too strong and that the
>> implication of 1 TeV rather than, say, 5 TeV was made in this sentence.
>>
>>
>> what about replacing
>>
>> "…masses of the order of 1 TeV"
>>
>> by
>>
>> "...masses below about 10 TeV"
>>
>> just as an example, ATLAS studies have shown sensitivity to KK gluons ->
>> ttbar in the 5 TeV range
>>
>> ------
>>
>> as far as the word "imply" goes, it seems to me that "imply" has a
>> built-in caveat that it is an implication on the basis of a certain logic.
>> In this case, the logic is that nature will avoid too much fine tuning. The
>> 10 TeV number would make the fine tuning about 0.01%
>> and the logic is that this is very uncomfortable amount of fine tuning
>>
>> So, I think we are protected in the legalistic sense if we do use the
>> word "imply"
>>
>> Also, to me, the scale of how "strong" the language is, is no longer set
>> by the "strength" of "there must be some new physics to explain massive
>> gauge bosons…" which worked very well for SSC and LHC motivation. I don't
>> think we have to normalize to that any more. I think we have to normalize
>> to the "strongest" language we could use for ANY new physics, in the
>> post-Higgs discovery, post-theta13, post-Planck…etc… world we live in now.
>>
>> regards,
>> Ashutosh
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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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