1. Budker INP, Novosibirsk
Super c/t factory
Budker INP, Novosibirsk
Bondar A.
ECFA, 12 March, 2011, Vienna

2. Physics at -charm factory
Precision charm physics
Precision charm precision CKM (strong phases, fD, fDs ,form-factors…)
Unique source of coherent D0/D0bar states (D0 mixing, CPV in mixing, strong phases for f3 measurements at SuperB and LHC)
Precision -physics with polarized beams
Lepton universality, Lorentz structure of -decay…
CP and T-violation in t and c decays
LFV decays (t->mg)
Second class currents (with kinematical constraints at threshold)
High statistic spectroscopy and search for exotics
Charm and charmonium spectroscopy
Spectroscopy of the highly exited Charmonium states (complimentary to Botomonium)
Light hadron spectroscopy in charmonium decays

3. Advantages of near threshold production
Particle multiplicity at 3.77 GeV is about two times lower than at 10.6 GeV
Close to threshold the additional kinematical constraints can suppress combinatorial background ( useful for second class currents studies)
Two body production e+e-DD. This allows to use double tag method:
fully reconstruct one D
then either fully reconstruct the other D (absolute branching ratios)
or look for events with one missing particle (leptonic, semileptonic decays)
Coherent production of D pairs allows to use quantum correlations for D-meson mixing and CP violation studies

4. Polarization Michel parameters CP-violation in -decays and/or LC
If even one beam polarized,  almost 100% longitudinally polarized near the threshold
Michel parameters
CP-violation in -decays and/or LC
CP-violation  new physics, charged Higgs
Two amplitudes with different weak and strong phases
Observables
Rate asymmetry: (+f+)-(-f)~sin sin
Triple product asymmetry (T-odd) (p1p2) T+-T-~cos sin
For complete description of matrix element , polarization and direction of  should be known
Polarization may increase sensitivity by several times

5. LFV decays  decay Current limit: ~ 310-8 by Belle with 7108 
Super-B, 75 ab-1
71010 -pairs
 decay
Current limit: ~ 310-8 by Belle with 7108 
At Y(4S):
ISR background e+e-+-
Upper Limit  1/L
tau-charm factory with 1010  will have better sensitivity

6. ISR Spectrum At near threshold
Eg for eettg background cannot be as high as Eg for tmg.
Background from eemmg will become more important.
 good MUID is essential.
Eg (CMS) from tmg and ISR(ttg)
U(4s)
maximum s
H.Hayahii 2008

7. Backgrounds Combinatorial background from t+t- events QED processes
Continuum background
Charm
Anything else?
t(mnn)t(pp0n)
2E=3.77GeV
t(mg)t(pn)
Level of the sensitivity c/t factory to Br(t->mg)<10-9

8. Quantum correlated DDbar states
Quantum correlated DD state decay is a instrument for strong phase measurement in the hadronic D-meson decays
D mixing contribution to the KSπ+π– Dalitz plot distributions for even and odd DD states is different. It can be used for CPV and Mixing parameters measurement in the time integrated mode !

9. D mixing in time integrated mode at c/t Factoryp- p+
e/m+ K- KS n
g/p0
Pure DD final state (ED(*) = Ebeam)
Equal to Y(3770) cross-section of DD
Low particle multiplicity ~6 charged part’s/event
Good coverage to reconstruct n in semileptonic decays
Pure JPC = 1- - initial state -
Flavor tags (K-+ ,K-+ 0,K-+ -+),
Semileptonic (Xe)
e+e- -> KSπ+π– + K+ p – (CLEO-c)

10. MC Sensitivity (KSπ+π–+ K+l –n ) 1ab-1
s(yD)=
s(xD)=
s(fCP)=2.3 o
s(|q/p|)=
If sensitivity of other states is comparable, the total statistical uncertainty should be 2-3 times better.

11. SuperB sensitivity

12. CLEOc Observation of e+e- -> hcp+p-
Ryan CHARM2010
Signal of Y(4260)→hc+- ?
 Rate of Yb→hb+- is high?
 Search for hb in (5S) data

13. CLEOc observation motivated Belle for hb search at Y(5S)
Preliminary
2S1S
3S1S
121.4 fb-1

14. Technical specifications for Super c/t factory
Beam energy from 1.0 to 2.5 GeV
Peak luminosity is 1035 cm-2s-1 at 2 GeV
Electrons are polarized longitudinally at IP
On-line energy monitoring (~5÷1010-5)
Main features of the Super c/t factory design
Two rings with Crab Waist collision scheme and single interaction point
Sub-mm beta-y at IP
Preserving of damping parameters (by 4 SC wigglers) through the whole energy range to optimize the luminosity
5 Siberian snakes to obtain the longitudinally polarized electrons for the whole energy range
Highly effective positron source (50 Hz top-up injection)
Polarized electron source
2.5 GeV full energy linac

15. Main ring schematically

16. Polarization degree vs energy

17. Luminosity betatron tune scan
CW advantage:
BB coupling resonances are suppressed
Dn~0.2 is feasible
Wide red area corresponds to 1035 cm-2s-1
Vertical tune
Horizontal tune

18. Super factories accelerator challenges
SB-INFN
Similar (Nanobeam/CW) approaches yield similar problems in accelerator design
All problems typical for Crab Waist/Nanobeam machines could be solved in collaborative manner by accelerator physicists

19. Detector Ultimate Hermeticity PID e/m/p/K separation up to 2GeV/c
CDC
TPC
ECL
Photon Detectors
SiPM
Aerogel Tiles
m momentum range in t->mg
Ultimate Hermeticity
PID e/m/p/K separation up to 2GeV/c
Momentum resolution
Low pT track efficiency
ECL energy resolution
Low energy (~20MeV) photons efficiency

20. Artistic view of future machine
Accelerator Complex MEuro
Detector MEuro
Buildings Construction and Site Utilities 50 MEuro

21. Project status and plans
CDR –in progress (to be ready in November 2011)
Collaboration is growing (now 10 Institutes from
Russia and 9 Institutes from other countries)
Design of the buildings –in progress (funded)
Injection complex - beginning of commissioning
Funding decision – end of 2012 ?
Construction ?