Dear Colleagues,

Chip and I received numerous technical comments on the long and short EF reports, 
and we are happy to get more.

Sally Dawson sent a long list, but only to the Higgs group.  I append her message
below.  In the meeting I would like to discuss the first of her comments, which is a
general issue about the introductory section. Please read this and think about it 
before the meeting:


Lines 68 and 69 and Section 1.2.2

 ….” call for new particles and forces at the TeV scale…”  This all assumes a
definition of naturalness.  Nowhere in the text do you mention arguments
(say Nima’s talk at Snowmass) against naturalness.  The split SUSY people
would say that all of the new physics is at a much higher scale than a few
TeV.  I am worried that you are overselling the case for TeV particles.


I would like to say that the omission of arguments against naturalness is
not an oversight; it is deliberate.  Naturalness might not be correct, and it
is certainly not precise, but there is no sharp argument against it nor any
predictive alternative.  I do believe that the case for new physics at the 
LHC has to be made on the basis of naturalness.  

If you, the Snowmass EF conveners, are not comfortable with this 
attitude, we can change the language.  However, this is a fundamental
point, and we need to talk about it.

Thanks,

Michael 


-------------------------------------------------------------------------------------------
  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/
---------------------------------------------------------------------------------------------
________________________________________
From: Sally Dawson [[log in to unmask]]
Sent: Wednesday, October 09, 2013 1:47 PM
To: Peskin, Michael E.; Raymond Brock; Chris Tully; Andrei Gritsan; Jianming Qian; Heather Logan
Subject: Fwd: My comments

Here are my somewhat picky comments.

Sally

---------- Forwarded message ----------
From: Sally Dawson <[log in to unmask]<mailto:[log in to unmask]>>
Date: Wed, Oct 9, 2013 at 11:06 AM
Subject: My comments
To: Andrei Gritsan <[log in to unmask]<mailto:[log in to unmask]>>, Chris Tully <[log in to unmask]<mailto:[log in to unmask]>>, Jianming Qian <[log in to unmask]<mailto:[log in to unmask]>>, "[log in to unmask]<mailto:[log in to unmask]>" <[log in to unmask]<mailto:[log in to unmask]>>, Heather Logan <[log in to unmask]<mailto:[log in to unmask]>>




Lines 68 and 69 and Section 1.2.2

 ….” call for new particles and forces at the TeV scale…”  This all assumes a

definition of naturalness.  Nowhere in the text do you mention arguments

(say Nima’s talk at Snowmass) against naturalness.  The split SUSY people

would say that all of the new physics is at a much higher scale than a few

TeV.  I am worried that you are overselling the case for TeV particles.

Lines 137 and 138 say that there must be a top partner at the TeV mass scale…. I

            would be much more comfortable saying “there is likely to be….”



Line 85 “particles at forces” should presumably be “particles and forces”



Eq. 1.1 and 1.2

            In Eq. 1.1 you use uppercase G, the rest of the document has lower case g.

            To get the sqrt(2) in eq. 1.2, you need Phi -> (v+h)/sqrt(2) in line 101



Eq. 1.8 uses uppercase H, the remainder of the text uses lc. h



Line 280,

There is a subtlety as to whether kappa_g etc include changes to the top coupling or just new particles which you might want to explain



Line 286

            Chiral fermions don’t decouple, so this statement isn’t true in an interesting

            way.



Line 289

            Kappa_V in the decoupling MSSM goes like 1/M**4



Line 304

            m_c really doesn’t matter for Higgs physics.



Line 314

            The LHC does measure the Higgs invisible width from Zh production—it’s

            just not very precise.



Line 320/321

            Where did you get the 12%  from?  It’s not what the Higgs cross section

            working group has.  Many of the Higgs coupling measurements come from

            VBF, which has a very small uncertainty.  Maybe you could add “significantly

            smaller for other….”



Around lines 330, missing a description of Fig. 1.4



Lines 340-342

            This is a model dependent statement.  The LHC probes the Higgs couplings of

            composite models and some singlet mixing models quite well.



Line 1009

            Is a 50% measurement really a measurement?



Line 1010, 1097

            Not sure what “deep” means



Lines 1028

            “great statistical and systematic sensitivity to BSM theories”  What do

            you mean here?  Do you mean Higgs couplings?  Precision measurements?



Line 1046 and 1061

            “Model independent”….. Doesn’t this assume MSSM-like couplings to the Z?

            What if I constructed a model where the new Higgs had a very small coupling           to the Z?

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