Transcript Slide 1

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CMS &ATLAS were designed and optimised to look beyond
the SM
 High -pt signatures in the central region
But…
‘incomplete’
( from the ILC motivation list)
• Main physics ‘goes Forward’
•Difficult background conditions.
• The precision measurements are limited by systematics
(luminosity goal of δL ≤5%)

Lack of :
•Threshold scanning
ILC chartered territory
•Quantum number analysing
•Handle on CP-violating effects in the Higgs sector
p
p
•Photon – photon reactions
p
RG
Is there a way out?
☺
X
YES-> Forward Proton Tagging
RG
Rapidity Gaps  Hadron Free Zones
Δ Mx ~ δM (Missing Mass)
p
p
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PLAN
1. Introduction
(a gluonic Aladdin’s lamp)
2.Basic elements of Durham approach
(a qualitative guide)
3. Prospects for CED Higgs production.
•
•
the SM case
MSSM Higgses in the troublesome regions
•
MSSM with CP-violation
(difficult oreven impossible with conventional methods)
4. Exotics
5. Conclusion
6. Ten commandments of Physics with
Forward Protons at the LHC
.
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Forward Proton Taggers as a gluonic
Aladdin’s Lamp
(rich Old and New Physics menu)
•Higgs Hunting (currently a key selling point).
• Photon-Photon
Physics.
• ‘Light’
( sparticle ‘threshold’ scan).
SUSY
K.Piotrzkowski
KMR-02
•Various aspects of Diffractive Physics
(strong interest from cosmic rays people
•Luminometry
)
KMOR-01
•High intensity Gluon Factory.
(lower lumi run, RG trigger…)
•Searches for new heavy gluophilic states
Helsinki Group, VAK
KMR-02
FPT
 Would provide a unique additional tool tc complement
the conventional strategies at the LHC and ILC.
a ‘ time machine’
Many of the studies can be done with L~10³³ (or lower)
Higgs is only a part of a broad diffractive program@LHC
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The basic ingredients of the KMR
approach
(1997-2005)
Interplay between the soft and hard dynamics
Sudakov
suppression
Bialas-Landshoff-91
( Born -level )
rescattering/absorptive
effects
Main requirements:
•inelastically scattered protons remain intact
•active gluons do not radiate in the course of evolution up
to the scale M
•<Qt> >>/\QCD
in order to go by pQCD book
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High price to pay for such a clean environment:
σ (CEDP) ~ 10
-4 σ( Incl)
Rapidity Gaps should survive hostile hadronic radiation
damages and ‘partonic pile-up ‘
W = S² T²
Colour charges of the ‘digluon dipole’ are screened
only at rd ≥ 1/ (Qt)ch
GAP Keepers (Survival Factors) , protecting RG against:
•the debris of QCD radiation with 1/Qt≥ ≥ 1/M
(T)
•soft rescattering effects (necessitated by unitariy)
(S)
Forcing two (inflatable) camels to go through the eye
of a needle
P
H
P
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schematically
skewed unintegrated structure functions (suPDF)
(x’~Qt/√s) <<(x~ M/√s) <<1
(Rg=1.2 at LHC)
T(Qt,μ) is the probability that a gluon Qt remains untouched in the
evolution up to the hard scale M/2
T + anom .dim. → IR filter
( the apparent divergency in the Qt integration nullifies)
<Qt>SP~M/2exp(-1/αs), αs =Nc/π αs Cγ
SM Higgs, <Qt>SP
≈2
GeV>> ΛQCD
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MAIN FEATURES
• An important role of subleading terms in fg(x,x’,Qt²,μ²),
(SL –accuracy).
• Cross sections
•
S^²
4
σ~ (fg )
KMR=0.026
( PDF-democracy)
(± 50%)
(detailed two-channel eikonal analysis of soft pp data)
SM Higgs at LHC
surprisingly good agreement with other ‘unitarizer’s approaches and
MCs.
^
• S²/b²
- quite stable (within 10-15%)
^
• S²~
s
-016
(Tevatron-LHC range)
• dL/d(logM² ) ~ 1/ (16+ M) 3.3
a drastic role of Sudakov suppression
•
σH ~ 1/M³
,
(~ 1/M³)
(σB) ch ~ Δ M/ M 6
• Jz=0 ,even P- selection rule for σ is justified
only if
<pt>² /<Qt>² « 1
8
pp
pp->p +M +p

(S²)γγ =0.86
we should not underestimate
αs²/8
photon fusion !
α²
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The advantages of CED Higgs production
• Prospects for high accuracy mass measurements
( ΓH and even lineshape in some MSSM scenarios)
mass window M = 3 ~ 1 GeV (the wishlist)
~4 GeV(currently feasible)
Helsinki Group
• Valuable quantum number filter/analyzer.
( 0++ dominance ;C

, P-even)
difficult or even impossible to explore the light Higgs CP at
the LHC conventionally.
(an important ingredient of pQCD approach,
otherwise, large
|Jz|=2 …effects,
~(pt/Qt)2 !)
• H ->bb ‘readily’ available
(gg)CED  bb LO (NLO,NNLO) BG’s -> studied
SM Higgs
S/B~3(1GeV/M)
complimentary information to the
conventional studies( also ՇՇ)
• H →WW*/WW - an added value
especially for SM Higgs with M≥ 135GeV, MSSM at low tanβ
•
New leverage –proton momentum correlations
(probes of QCD dynamics, pseudoscalar ID,
CP violation effects)
KMR-02; A.Kupco et al 04; V.Petrov et al -04; J.Ellis et al -05
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☻Experimental Advantages
– Measure the Higgs mass via the missing
mass technique
Mass measurements do not involve Higgs
decay products
Experimental Challenges
– Tagging the leading protons
– Selection of exclusive events & backgrounds
– Triggering at L1 in the LHC experiments
– Model dependence of predictions:
(soft hadronic physics is involved after all)
– resolve some/many of the issues with
Tevatron data
There is a lot to learn from present
and future Tevatron diffractive data
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Current consensus on the LHC Higgs
search prospects
(e.g, A.Djouadi, Vienna-04; G.Weiglein, CMS, 04; A.Nikitenko,UK F-m,04))
•SM Higgs : detection is in principle guaranteed
for any mass.
☺
•In the MSSM h-boson most probably cannot ☺
escape detection ,and in large areas
of parameter space other Higgses can be found.
•But there are still troublesome areas of the
parameter space:
intense coupling regime,
MSSM with CP-violation…..

•More surprises may arise in other SUSY
non-minimal extensions
• After discovery stage (Higgs identification):
The ambitious program of precise measurements of the
mass, width, couplings,
and, especially of the quantum numbers and
CP properties would require an interplay
with a ILC
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SM Higgs Cross Section * BR
Cross sections ~O(fb)
Diffractive Higgs
mainly studied for
Hbb
-K(KMR)97-04
-DKMOR-02
Boonekamp et al. ,01-04
Petrov et al. ,04
 Recently study
extended
for the decay into
WW*,WW
can reach higher
masses
‘Leptonic trigger cocktail’
(WW,bb,ZZ,)
work in progress, FT420
UK team
Note Hbb (120 GeV) at Tevatron  0.13 fb
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SM Higgs, CEDP
LHC, L=30fb-1
KMR-00,KKMR-03,DKMOR-02
M(GeV)
120
140
comments
accuracy could be improved
σ
3fb
1.9fb
(1 -5.5fb)
(0.6 -3.5fb)
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3.5
Sbb
(theory +experim., CEDP dijets )
cuts + efficiences.
(S/B)bb 3(1GeV/M) 2.4(1GeV/ M)
cuts +effic.
LO,NLO,NLLO
BG
ϭH (M=120GeV)= 3fb for reference purposes.
natural low limit 0.1fb (photon fusion)
H->WW
(with full CMS detector simulation)
B.Cox, A. De Roeck, VAK ,M.Ryskin,
T.Pierzchala,W.J.Stirling et al
M(GeV)
140
150
SWW (LH)
6.3
9
160
12.6
work in progress
with leptonic ‘trigger cocktail ‘ we can go up in mass with a detectable signal up to 200 GeV
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Exclusive SM Higgs production
b jets :
MH = 120 GeV s = 2 fb (uncertainty factor ~2.5)
MH = 140 GeV s = 0.7 fb
MH = 120 GeV : 11 signal / O(10) background
in 30 fb-1
(with detector cuts)
H
WW* :
MH = 120 GeV s = 0.4 fb
MH = 140 GeV s = 1 fb
MH = 140 GeV : 8 signal / O(3) background
in 30 fb-1 (with detector cuts)
•The b jet channel is possible, with a good understanding of
detectors and clever level 1 trigger (needs trigger from the central
detector at Level-1)
•The WW* (, ZZ*…) channel is extremely promising : no trigger
problems, better mass resolution at higher masses (even in leptonic
/ semi-leptonic channel), weaker dependence on jet finding
algorithms
•If we see SM-like Higgs + p- tags  the quantum numbers are 0++
H
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☺
An added value of the WW channel
1. ‘less demanding’ experimentally
(trigger and mass resolution requirements..)
allows to avoid the potentially difficult issue of triggering
on the b-jets
2. higher acceptances and efficiencies
3. an extension of well elaborated conventional program,
(existing experience, MC’s…)
4. the decrease in the cross section is compensated for
by the increasing Br and increased detection efficiency
5. missing mass resolution improves as MH increases
6. the mass measurement is independent of the decay
products of the central system
7. Better quantitative understanding of backgrounds.
Very low backgrounds at high mass.
8. 0+ assignment and spin-parity analyzing power
- still hold
☻ we should not ignore MSSM with low tan β
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The yield of WW/ bb for CED production of the SM Higgs
H→WW
H→bb
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MSSM with low tan β
 LEP
low tan β exclusion bounds weaken if the top mass goes up
(Karlsruhe group- 99)
 with new Mt we should pay
scenarios
more attention to the low tan β
M(GeV)
Mind the mass gap
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γγ-backgrounds
Quic kTime™ and a
TIFF (Uncompressed) decompressor
are needed to see this pic ture.
Calculated using CalcHEP
(T.Pierzchala -05)
with centrality cuts (|h| < 2.5 leptons and jets) and M
= 0.05 MH ,MH = 120 GeV (140 GeV) (WW*) = 0.06 fb
(0.12 fb)
Note : these can be reduced, if/when necessary, by pT > 100
MeV cut on protons. Mass resolution is conservative here)
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gg backgrounds
Quic kTime™ and a
TIFF (Uncompressed) decompressor
are needed to see this pic ture.
VAK, M.Ryskin & W.J.Stirling 05
(MH = 140 GeV) = 0.8 fb
Estimate reduction of BGs by
factor of ~ 10 from jet /
proton pT cuts above WW
threshold - more work needed
below threshold.
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Quic kTime™ and a
TIFF (Uncompressed) decompressor
are needed to see this pic ture.
WW / WW* Summary
• Trigger is no problem
• S/B ~ 1 (much better above
WW threshold)
• expect to see double tagged
SM Higgs up to ~180
~200 GeV with
increasing precision on mass
• MSSM low tan b results are
encouraging
• The advantages of forward proton
tagging are still explicit
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The MSSM and more exotic
scenarios
If the coupling of the Higgs-like
object to gluons is large, double
proton tagging becomes very
attractive
• The intense coupling regime of the MSSM
(E.Boos et al, 02-03)
• CP-violating MSSM Higgs physics (A.Pilaftsis,98; M.Carena et al.,00-03, B.Cox et
al 03, KMR-03, J. Ellis et al -05)
Potentially of great importance for electroweak baryogenesis
• an ‘Invisible’ Higgs
(BKMR-04)
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Higgs couplings
(G.Weiglein)
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(a )The intense coupling regime
MA ≤ 120-150GeV, tan β >>1 ( E.Boos et al,02-03)
•h,H,A- light, practically degenerate
•large Γ, must be accounted for
• the ‘standard’ modes WW*,ZZ*, γγ …-strongly
suppressed v.s. SM
•the best bet – μμ -channel,
in the same time – especially advantageous for CEDP:
☺
(KKMR 03-04)
• σ(Higgs->gg)Br(Higgs->bb) - significantly
exceeds SM.
thus ,much larger rates.
• Γh/H ~ ΔM,
•0- is filtered out, and the h/H separation may
be possible
•(b) The intermediate regime: MA ≤ 500 GeV,
tan β < 5-10
(the LHC wedge, windows)
(c) The decoupling regime
MA>> 2MZ
(in reality, MA>140 GeV, tan β>10)
h is SM-like, H/A -heavy and approximately degenerate,
CEDP may allow to filter A out
~
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The MSSM can be very proton tagging friendly
The intense coupling regime is where
the masses of the 3 neutral Higgs
bosons are close to each other and
tan b is large
suppressed
enhanced
0++ selection rule suppresses
A production:
CEDP ‘filters out’
pseudoscalar production,
leaving pure H sample for
study
MA = 130 GeV, tan b = 50
Mh = 124 GeV : 71 signal /
3background/GeV in 30 fb-1
MH = 135 GeV : 124 signal / 2
background/GeV in 30 fb-1
MA = 130 GeV : 3 signal / 2
background/GeV in 30 fb-1
for 5 ϭ
BR(bb) > 0.7fb (2.7fb) for 300 (30fb-1)
Well known difficult region for conventional channels, tagged
proton channel may well be the discovery channel, and is
certainly a powerful spin/parity filter
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SM Higgs: (30fb-1)
11 signal events (after cuts)
O(10) background events
100 fb
Cross section factor
~ 10-20 larger in MSSM
(high tanb)
KKMR-03
Study correlations
1fb
between the outgoing
protons to analyse the
spin-parity structure of
the produced boson
A way to get information
on the spin of the Higgs
 ADDED VALUE
to
the LHC
120 140
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decoupling
regime:
mA ~ mH large
h = SM
intense coupl:
mh ~ mA ~ mH
,WW.. coupl
suppressed
with CEDP:
•h,H may be
clearly
distinguishable
outside130+-5
GeV range,
•h,H widths are
quite different
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SM pp  p + (Hbb) + p
S/B~11/4(M)
with M (GeV) at LHC with 30 fb-1
e.g. mA = 130 GeV, tan b = 50
(difficult for conventional detection,
but CEDP favourable)
S
mh = 124.4 GeV 71
mH = 135.5 GeV 124
mA = 130 GeV
1
B
3
2
2
x M/ 1GeV
incredible significance (10 σ) for Higgs signal even
at 30 fb -1
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Helping to cover the LHC gap?
needs update
With CEDP the mass range up to 160-170 GeV can be covered at medium
tanb and up to 250 GeV for very high tan b, with 300 fb-1
Needs ,however, still full simulation
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Spin Parity Analysis
Azimuthal angle between the leading protons depends on spin of H
 angle between protons
 angle between protons with
rescattering effects included
• Azimuthal angle between the
leaprotons depends on spin
of H
• Measure the azimuthal angle
of the proton on the proton
taggers
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KKMR -03
Probing CP violation in the Higgs Sector
Azimuthal asymmetry
in tagged protons
provides direct
evidence for CP
violation in Higgs
sector
‘CPX’
scenario
( in fb)
KMR-04
CP even
CP odd
active at
non-zero t
A is practically uPDF - independent
Ongoing studies - are there regions of MSSM parameter space
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where there are large CP violating couplings AND enhanced gluon
couplings?
Recent development
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CP- violating MSSM with large tri-mixing
J.Ellis et al 05
tan β=50, MH+=150 GeV
In the tri-mixing scenario we expect ϭbb ~ 1fb and proton asymmetries A ~0.1-03
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Summary of CEDP
• The missing mass method may provide unrivalled
Higgs mass resolution
•Real discovery potential in some scenarios
• Very clean environment in which to identify the
Higgs,for example, in the CPX scenario
• Azimuthal asymmetries may allow direct
measurement of CP violation in Higgs sector
• Assuming CP conservation, any object seen with
2 tagged protons has positive C parity, is (most
probably) 0+, and is a colour singlet
e.g. mA = 130 GeV, tan b = 50
(difficult for conventional detection,
but exclusive diffractive favourable)
L = 30 fb-1
mh = 124.4 GeV
mH = 135.5 GeV
mA = 130
GeV
S
71
124
1
X
B
3 events
2
M
1 GeV
2
► WW*/WW modes are looking extremely attractive.
Detailed studies are underway (UK FT420 team)
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Exotics



Gluinoniums
An ‘Invisible’ Higgs
Gluinonium (gluinoball)
~~
: G=gg
~
scenarios where gluino g is the the LSP (or next- to-LSP)
currentntly hit of the day -split -SUSY
the lowest-lying bound state 0++ (³ P0 )
the energies of P-wave states
En= -9/4 mg~ αs²/n² (n ≥2)
~~
G – a ‘Bohr atom’ of the g g- system
ΓG= (MG/100 GeV)
0.33 MeV,
σG=30 fb (MG/100 GeV) 5
-2
(S/B)gg= 0.25 !0
(1/ΔM) (MG/ 100 GeV)
visualization is challenging even with angular cuts
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►
an ‘Invisible ‘ Higgs
KMR-04
M.Albrow & A .Rostovtsev -00
several extensions of the SM: a fourth generation,
some SUSY scenarios,
large extra dimensions
(one of the ‘LHC headaches’ )
the advantages of the CEDP – a sharp peak in the
MM spectrum, mass determination, quantum
numbers
strong requirements :
• triggering directly on L1 on the proton taggers
•low luminosity : L= 10
• forward
calorimeter
³² -10 ³³ cm -2 sec-1
(…ZDC)
(pile-up problem) ,
(QED radiation , soft DDD),
• veto from the T1, T2- type detectors
(background reduction,
improving the trigger budget)
 various potential problems of the FPT approach reveals themselves
 however there is a (good) chance to observe such an invisible object,
which otherwise may have to await a ILC
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The physics case for proton tagging
• If you have a sample of Higgs candidates, triggered
by any means, accompanied by proton tags, it is a 0++
state.
• The mass resolution will be better than central detectors
(e.g. H -> WW -> nl jj … no need to measure missing ET)
• With a mass resolution of ~O(1 GeV )the standard
model Higgs b decay mode opens up, with S/B > 1
• In certain regions of MSSM parameter space,
S/B > 20, and double tagging is THE discovery
channel
• In other regions of MSSM parameter space,
explicit CP violation in the Higgs sector shows up as
an azimuthal asymmetry in the tagged protons ->
direct probe of CP structure of Higgs sector at LHC
• Any 0++ state, which couples strongly to glue, is a
real possibility (radions? gluinoballs? etc. etc.)
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EXPERIMENTAL CHECKS
•Up to now the diffractive production data are consistent with
K(KMR)S results
Still more work to be done to constrain
the uncertainties
•Very low rate of CED high-Et dijets ,observed yield
of Central Inelastic dijets.
(CDF, Run I, Run II)
data up to (Et)min>50 GeV
• ‘Factorization breaking’ between the effective diffractive
structure functions measured
at the Tevatron and HERA.
(KKMR-01 ,a quantitative description of the results,
both in normalization and the shape of the
distribution)
•The ratio of high Et dijets in production with one
and two rapidity gaps
•The HERA data on diffractive high Et dijets in
Photoproduction.
(Klasen& Kramer-04 NLO analysis)
•Preliminary CDF results on exclusive charmonium
CEDP. Higher statistics is underway.
•Energy dependence of the RG survival (D0, CDF)
• CDP of γγ, data are underway
KKMR .….. has still survived the exclusion limits
set by the Tevatron data…. (M.Gallinaro, hep-ph/01410232)
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CONCLUSION
Forward Proton Tagging would significantly
extend the physics reach of the ATLAS
and CMS detectors by giving access to a wide
range of exciting new physics channels.
For certain BSM scenarios the FPT may be the
Higgs discovery channel within the first
three years of low luminosity running
 FPT may provide a sensitive window into
CP-violation and new physics
 Nothing would happen unless the
experimentalists come FORWARD and
do the REAL WORK
We must work hard here – there is no easy solution
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Proposed UK project to launch activity
Forward proton tagging at the LHC as a means to discover
new physics
• Proposal for a project submitted to PPARC (UK)
R. Barlow1,7, P. Bussey2, C. Buttar2, B. Cox1, C. DaVia3, A. DeRoeck4, J. R. Forshaw1, G. Heath5, B.
W. Kennedy6, V.A. Khoze4, D. Newbold5, V. O’Shea2, D. H. Saxon2, W. J. Stirling4, S. J. Watts3
1. The University of Manchester, 2. The University of Glasgow, 3. Brunel University, 4.
IPPP Durham, 5. Bristol University, 6. Rutherford Appleton Laboratory, 7. The
Cockroft Institute
•
Request for funds for
– R&D for cryostat development
– R&D for detectors (3D silicon so far)
– Studies for trigger/acceptance/resolution
• Total of order 2.106 pounds been asked for 20052008 period. Covers 2 cryostats, manpower
(engineers), detector design study
 Has received go ahead (with some boundary conditions)
 If launched, other (non-UK) groups in CMS could kick in!!
Opportunities for present/new collaborators
to join Forward Physics .
Start international collaboration now
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New Forward Detector Proposal (in prep.)
Cold region
420 m region: connecting (empty cryostat)

Acceptance of 200m is not sufficient fot Higgs detection
Proposal to study a modification of the cryostat and to operate compact
detectors in the region of 400m (for ATLAS & CMS)
R&D collaboration building: UK groups, Belgian & Finish institutes, CERN…
US420 (consortium of US groups who are on CMS & ATLAS)
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of Forward Proton Tagging
1. Thou shalt not worship any other god but the First Principles,
and even if thou likest it not, go by thy Book.
2. Thou slalt not make unto thee any graven image,
thou shalt not bow down thyself to them . (non-perturbative Pomeron)
3.Thou shalt treat the existing diffractive experimental
data in ways that show great consideration and respect.
4. Thou shalt
draw thy daily guidance from the standard
candle processes for testing thy theoretical models.
5. Thou shalt remember the speed of light to keep it holy.
(trigger latency)
6.Thou shalt not dishonour backgrounds and shalt study
them with great care.
7.Thou shalt not forget about the pile-up (an invention of Satan).
8. Though shalt not exceed the trigger threshold and
the L1 saturation limit. Otherwise thy god shall
surely punish thee for thy arrogance.
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9. Thou shalt not annoy machine people.
10. Thou shalt not delay, the LHC start-up is approaching
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