# Presentation: 119280

## GTeV: Gluon Physics at the Tevatron

- A future experiment at the Tevatron
- 2009: CDF & D0 complete data taking
- BTeV to run (if funded) 2009- ~ 2013 (?)
- Primary Goal of GTeV: QCD (perturbative & non-perturbative)
- Uses CDF or D0 detector as “core”
- Add precision forward and very forward tracking

## Primary Goal: Understand Strong Interactions

**Foci:**
**        ****Gluon density g(x, Q2) at very low x**
**             **saturation, unitarity, gluodynamics, non-perturbative frontier
**        ****Pure Gluon jets**** **
**               **profiles, content, color connection, gg compared to q-qbar jets
**        ****Determine glueball spectrum**
-               Relates to pomeron trajectories, strings, lattice ...
-          **Measure exclusive**
-                 Relates to SM Higgs study at LHC
**        ****Discover new exotic hadrons**
-                Hybrids, 4-quark, pentaquarks, ...
**        ****Search for exotic fundamentals**
**            **CP-odd H,** **Radions, gluinoballs          ...

## Use Tevatron as Tagged Gluon-Gluon Collider

- Glueballs and Hybrids
-              New Exotic Hadrons
-                      chi_c and chi_b states
-                                Hunting strange exotic animals (radions, ...?

- tag

- tag

- Everywhere: **Gluodynamics**, perturbative and non-perturbative issues

- (Stretch Goal)

## The REAL Strong Interaction

- point-like, weak coupling
- perturbative

- extended, strong coupling
- non-perturbative

- Many approaches, none complete:
-  Lattice Gauge Theory
-    Small volume, hadron size
-  Regge Theory: Analyticity +
-    Unitarity + Crossing Symmetry
-     + Complex angular momenta
-  String models

_**Want a complete understanding of S.I.**_
**Non-perturbative – perturbative transition**

## Some of proposed program could be done now, except:

- 1)  Do not have 2-arm forward p-taggers (dipole spectrometer)
- 2)  Small angle ( < 3 deg) region trackless
- 3)  Limit on number of triggers
- 4)  Bandwidth allocated small
**        **
**       ****60 Hz ******** 250 Hz ******** > 1 KHz for 2009  [       /year]**
-        CDF, D0:  NP QCD <~ 10%,     other ~ 90%
-        **GTeV:      NP QCD ~ 90%,     other <~ 10%**
-      &   upgrade of forward and very forward detectors

## Probing Very Small x Gluons

- High parton densities
- New phenomena (gluon saturation)
- HERA measures q(x) to ~ 10^-5
- g(x) by evolution, charm
- GTeV : measure g(x) to ~ 10^-4
- (also x >~ 0.5) more directly

- Instrument                   region with tracking,
- calorimetry (em+had), muons,
- jets, photons ...

## Gluon Jets

- LEP(Z) ... ~ 10^7 q-jets, detailed studies
- “Pure” g-jet sample: 439 events (OPAL), Delphi more but 80% “pure”

- (2 jets and ~ nothing else)
- > ~ 99% pure g-jets
- q-jets suppressed by Jz = 0 rule

- g-jet contaminated at low-x

- Fragmentation, scaling
- color singlet back-to-back gg jets: DPE unique

## Central Exclusive Production

- ... or, diffractive excitation of the vacuum

- “It is contrary to reason to say that there is a vacuum
- or a space in which there is absolutely nothing.”
-                                                                                                 Descartes

-  Virtual states in the vacuum can be promoted to real states
-       by the glancing passage of two particles.
- Charged lepton (or q) pairs : 2-photon exchange
- Hadronic states : 2-pomeron exchange (DPE) dominates
- Vacuum quantum number exchange.
- Central states’ quantum numbers restricted.
- Measure forward p,pbar  missing mass, Q-nos.
- Ideal for Glueball, Hybrid spectroscopy

## Gluonia and Glueballs

- Hadrons G without valence quarks
- Allowed in QCD – or, if not, why not ?
- Some can mix with         mesons
- Some have exotic quantum numbers and cannot
- Glue-glue collider ideal for production (allowed states singly,
- others in association GG’, G + mesons.)
- Forward          selects exclusive state, kinematics filters Q.Nos :
- Exclusive central states e.g.

- Other processes:

- This one 

## Central Exclusive Production

_***Central Exclusive Production***_

- gg fusion: main channel for H production.
- Another g-exchange can cancel color, even leave p intact.
-                        p p  p    +    H     +      p
- Theoretical uncertainties in cross section, involving skewed
- gluon distributions, gluon k_T, gluon radiation, Sudakov form factors
- Probably                 ~ 0.2 fb at Tevatron, not detectable, but
- may be possible at LHC (higher L and     ~ 3 fb?)

- Khoze,Martin,Ryskin hep-ph/0111078
- Lonnblad & Sjodahl hep-ph/0311252
- and many others

## If MM resolution <~ 100 MeV, exclusive test, resolve states

- Predictions for Tevatron:  Khoze, Martin, Ryskin ~ 600 nb
-                                           Feng Yuan    ~ 735 nb (20 Hz at Tevatron!)

- (Angela Wyatt)

- Measuring forward p  central quantum numbers
-                  ;      2++ suppressed at t=0 for         state
-                                                                                     (Khoze,Martin,Ryskin hep-ph/0011393; F.Yuan hep-ph/0103213)

- ===========================

## Beyond the Standard Model

_**CP-odd Higgs**_ : allowed 20 < M < 60 GeV
- Don’t couple to W,Z ... produced by gg  t-loop  h
- But b-bbar b/g large too ... Mass resolution critical

_**Radions**_** **: Quantum fluctuations in 5th dimension: tensor + scalar
- 20 GeV and up allowed if parameters right. Like h but gg coupling high
- Width ~ keV, Decay  b bbar

_**Light Gluinos and Gluinoballs**_

- Gluino      could be lightest SUSY particle LSP Does not decay in detector --- forms heavy hadrons. Can form           bound states “gluinoballs”

## Missing Mass!

- Extreme case of rest of detector completely empty
- No MM peaks “expected”
- But threshold bump  pair production of e.g. LSPs
- Needs measurement of all forward particles
- Tracking + dipoles (?)
- Background from double beam halo:
- Timing (<~30 ps) on pots, Luminosity dependence

- ET as 3rd axis?

## Single Diffractive Excitation

- System X can be soft (all low pT)
- or hard (jets, W, Z).
- HERA-Tevatron difference – universal screening?
- Pomeron trajectory probably different for
- hard and soft systems. Similar seen at HERA in

- Systematic study of trajectories, needs s-dependence
- run at sqrt{s} = 630, 900, 1300, 1960 GeV
- (~ log spacing, modest runs at lower sqrt{s})

- s

## BFKL and Mueller-Navelet Jets

- Color singlet (IP) exchange between quarks
- Enhancement over 1g exchange – multiRegge gluon ladder
- Jets with large y separation
- n minijets in between (inelastic case)
- large gap in between (elastic case)

- Fundamental empirical probe of new regime:
- non-perturbative QCD at short distances.

## Hadron Spectroscopy: an example

_***Hadron Spectroscopy: an example***_

- X(3872) discovered by Belle (2003)
- Seen soon after by BaBar and CDF
- Relatively narrow

- What are its quantum numbers?
- Why so narrow? What is it?

- Also, cross-section depends
- on “size/structure” of state.

- If we see in exclusive DPE:

## Bjorken: Low pT is the frontier of QCD

- As pT drops from **200 ******** 100 ******** 50  MeV** what happens?
- Larger distances: 1 f   4 fm
- How do gluon fields in protons “cut off” ?
- Multiplicity distributions of very low pT particles, correlations, ...
- Low-pT cloud in special events
- [Runs with reduced field, Si-only tracking, etc
- ...................absorption and multiple scattering is limit]
- Large impact parameter, b, collisions
- RHIC AA can measure b, how can we?   Diffraction at small t

## Detectors

- Add:
- New pots very forward E&W: through quadrupoles + near (55m) + far (~160m?)
- Other forward detectors (tracking, upgrade calorimetry e.g.)  **“Cone Spectrometers”**
- New DAQ and trigger system  kHz
- Silicon (certainly want it) ... hope it’s still good (COT also)

- D0 an option.
- I focus on CDF
- (tracking, hadron ID
- dE/dx, TOF)

- MiniPlugs

## CDF Silicon VerteX Detector SVX

_***CDF Silicon VerteX Detector SVX***_

- For beauty, charm, tau identification and measurement.
- ~ 720,000 strips, 25um with 50um readout
- L00 : ~ 1.5 cm from x, R-phi view
- SVXII: 3 double 90 deg layers + 2 double 1.2 deg layers
- ISL : 1 or 2 double 1.2 deg layers.
- Impact parameter resolution ~ 30 um @ 1 GeV/c

## CDF Central Outer Tracker (COT)

- Drift chamber
- 3.1m in z, 0.34-1.32m in R
- 96 layers  30,240 s.wires
- 40 um gold-plated tungsten
- ADC & TDC each end
- 6 um Au-mylar field sheets
- Resolution ~ 150 um/wire

## New Forward Region (0.5-3.0 deg): Cone Spectrometer?

- Now: 48 CLC counters + MiniPlugs

- Can (remove Q1 and) push back ~ 2 m low-beta quads
- Tracking e.g. GEM layers (50 um, 15 ns) over large area
- Deeper Calorimeter (~8 int. lengths) high granularity, em/had
- Possibility of forward dipoles (?) or toroid fields on calo iron
- Upgrade motivation: Low-x with v.forward jets, J/psi
- (BFKL) J - minijets - J, J – gap – J and J + X + J     ... etc
-                             “Cone Spectrometers”

## Very Forward: Roman Pots

_***Very Forward: Roman Pots***_

- D0 has 8+8 quadrupole spectrometer pots + 2 dipole spectrometer pots
- Scintillating fiber hodoscopes (~ 1mm)

- CDF has 3 dipole spectrometer pots
- 0.8 mm x-y fibers

- GTeV: Quads + near + far dipoles
- Silicon ustrips, pixels, trig scint
- Quartz Cerenkov for ~ 30 ps TOF

## Add : New/upgrade pots very forward E&W: quad + near (55 m) + far (160 m?)Forward (“cone”) region probably not instrumentable

- Add : New/upgrade pots very forward E&W: quad + near (55 m) + far (160 m?)Forward (“cone”) region probably not instrumentable

_***Re-using D0 detector?***_

## Tevatron Issues

- Spaces for pots and their position: quad, near dipole, far dipole
**Replace 3 dipoles with 2 High Field dipole(s)**  ~ 4 m spaces
- 6.5 Tesla, same current, temperature!   (Tech.Div or outside)
-                                                          critical path, ~ 4 years
- Momentum and Missing mass resolution Limits? Medium-beta?
- p-z correlation? stability, drifts
- Instrumentation: precision (~ 10 um?) BPMs at pots
- Co-existence with BTeV: Luminosity (~2-4 e31 also high?),
- Beam-beam tune shift, Long-range tune shift,
- Electrostatic separators, Luminosity lifetime, ...

## Many Subjects not Covered

**The cosmic ray connection:**** ****very forward particle production                           data needed**
**Jet – gap - X – gap - Jet****   ( low mass X) ****different from p—X---p ?**
**Very soft photons ****< 100 MeV, via conversions**
**p ******** 3 jet**** fragmentation: ****3 very forward jets, with & without gaps**
**Bose-Einstein correlations: ****directional, event type, high statistics**
**Many other studies will be done,**** as happens in CDF & D0 now.**

_***Many Subjects not Covered***_

## The Future of QCD at the Tevatron

- Physics	Low Mass Double Pomeron
- 	High Mass DPE & Higgs
- 	Jet-Gap-Jet Studies+BFKL
- 	Small-x g and g-jets
- 	Hadron spectroscopy
- 	Single Diffractive Excitation
-                             Exotics
- 	Cosmic Ray issues
- 	Event Generators
- Detectors	Simulations with Detectors
- 	Cone Spectrometers
- 	Roman pots ("v.forward")
-                              Central detector
- (DAQ & Trigger)	Triggers L1 L2 L3
- 	kHz DAQ
- 	Computing on/off line, GRID
- Tevatron	High Field Dipoles
- 	Orbit issues, beta, ES seps
- 	Roman Pot insertions
- 	BTeV-GTeV interaction

- Forming Working Groups, conveners.
- Workshop at Fermilab May 20-22 :
_***The Future of QCD at the Tevatron***_
- CDF & D0 now  2009
- HERA, BNL, JLab, etc
- BTeV, LHC beyond 2007
- What is unique for GTeV beyond 2009?
- Please come!

_***GTeV plan***_

**Proposal** to PAC Spring 2005 (?)

##                                                              Let’s do it!

- There will be a vast amount of QCD physics still
- to be done in 2009. Here I have only scratched the surface.
- Unknown territory: discoveries likely.
- The CDF and D0 detectors are great central detectors for this
- program, suitably upgraded at modest cost:
- DAQ, trigger, forward (few deg) and very forward (pots)
- Not all ~1500 physicists on CDF and D0 want to go to LHC
- We hope physicists come from DESY, BNL, JLab etc expts.
- Tevatron running anyway for BTeV, so it’s great value.
-                                                              **Let’s do it!**