Tau and Charm physics at a Super c/ factory Bondar A. Budker INP, Novosibirsk.
Super c/ t factory Budker INP, Novosibirsk Bondar A.
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Transcript of Super c/ t factory Budker INP, Novosibirsk Bondar A.
Super c/ factory
Budker INP, Novosibirsk
Bondar A.
ECFA, 12 March, 2011, Vienna
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 3 measurements at SuperB and LHC)
• Precision -physics with polarized beams– Lepton universality, Lorentz structure of -decay…– CP and T-violation in and c decays– LFV decays ()– 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
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
Polarization
•Michel parameters
•CP-violation in -decays and/or C• 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) (p1p2)
T+-T-~cos sin• For complete description of matrix element ,
polarization and direction of should be known– Polarization may increase sensitivity by several
times
If even one beam polarized, almost 100% longitudinally polarized near the threshold
LFV decaysSuper-B, 75 ab-1
71010 -pairs
• decay •Current limit: ~ 310-8 by Belle with 7108 •At Y(4S):
ISR background e+e-+-Upper Limit 1/L
• tau-charm factory with 1010 will have better sensitivity
ISR Spectrum At near threshold
– E for ee background cannot be as high as E for .
– Background from ee will become more important. good MUID is essential.
s =10.58GeV s =5.0GeV
s =4.25GeV s =4.0GeV
E (CMS) from and ISR()
(4s)
maximum
H.Hayahii 2008
Backgrounds
•Combinatorial background from +- events
•QED processes •Continuum background•Charm•Anything else?
()(0)
()()
2E=3.77GeV
Level of the sensitivity c/ factory to Br(->)<10-9
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 !
Quantum correlated DDbar states
Pure DD final state (ED(*) = Ebeam)
Equal to cross-section of DDLow particle multiplicity ~6 charged
part’s/eventGood coverage to reconstruct in
semileptonic decaysPure JPC = 1- - initial state - Flavor tags (K-+ ,K-+ 0,K-+ -+), Semileptonic (Xe)
e+ e
*0D
0D
+
e/+
K
KS
D mixing in time integrated mode at c/
Factory
e+e- -> KSπ+π– + K+ – (CLEO-c)
(yD)=0.9 10-3
(xD)=1.3 10-3 (CP)=2.3 o
(|q/p|)=3.6 10-2
)()(
)()(
asymi
asymi
asymi
symi
iKK
KKf
MC Sensitivity (KSπ+π–+ K+l – ) 1ab-
1
If sensitivity of other states is comparablethe total statistical uncertainty should be 2-3 times better.
SuperB sensitivity
Ryan Mitchell @ CHARM2010
Signal of Y(4260)→hc+- ?
Search for hb in (5S) data
Rate of Yb→hb+- is high?
CLEOc Observation of e+e- -> hc+-
13
2S
1S
3S
1S
Preliminary
121.4 fb-1
CLEOc observation motivated Belle for hb search at Y(5S)
• 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÷1010-5)
• 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
Technical specifications for Super c/ factory
Main features of the Super c/ factory design
Main ring schematically
Polarization degree vs energy
Luminosity betatron tune scan
CW advantage:
BB coupling resonances are suppressed
is feasible
Wide red area corresponds to 1035 cm-2s-1
Horizontal tune
Ve
rtic
al tu
ne
Super factories accelerator challenges
Similar (Nanobeam/CW) approaches yield similar problems in accelerator designAll problems typical for Crab Waist/Nanobeam machines could be solved in collaborative manner by accelerator physicists
SB-INFN
Detector
PID
PIDCDC
TPC
ECL
Photon Detectors
SiPM
Aerogel Tiles
•Ultimate Hermeticity •PID e///K separation up to 2GeV/c•Momentum resolution•Low pT track efficiency•ECL energy resolution•Low energy (~20MeV) photons efficiency
momentum range in ->
Artistic view of future machine
• Accelerator Complex 200 MEuro
• Detector 80 MEuro
• Buildings Construction and Site Utilities 50 MEuro
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 2012-2017?