SuperB SuperB Status and ProspectsStatus and Prospects

M. E. Biagini, LNF-INFNfor the SuperB and DAΦΦΦΦNE Teams

9th ICFA Seminar, SLAC, Oct. 29 th 2008

M. E. Biagini, M. Boscolo, A. Drago, S. Guiducci, M. Preger, P. Raimondi, S. Tomassini, C. Vaccarezza, M. Zobov (INFN/LNF, Italy), K. Bertsche, Y. Cai, A. Fisher, S. Heifets, A. Novokhatski, M.T. Pivi, J. Seeman, M. Sullivan, U. Wienands, W. Wittmer (SLAC, US), T. Agoh, K. Ohmi, Y. Ohnishi (KEK, Japan), I. Koop, S. Nikitin, E. Levichev, P. Piminov, D. Shatilov (BINP, Russia), A. Wolski (Cockcroft, UK), M. Venturini (LBNL, US), S. Bettoni (CERN, Switzerland), A. Variola (LAL, France), E. Paoloni, G. Marchiori (Pisa Univ., Italy)

D. Alesini, M. E. Biagini, C. Biscari, R. Boni, M. Boscolo, F. Bossi, B. Buonomo, A. Clozza, G. Delle Monache, T. Demma, E. Di Pasquale, G. Di Pirro, A. Drago, A. Gallo, A. Ghigo, S. Guiducci, C. Ligi, F. Marcellini, G. Mazzitelli, C. Milardi, F. Murtas, L. Pellegrino, M. Preger, L. Quintieri, P. Raimondi, R. Ricci, U. Rotundo, C. Sanelli, M. Serio, F. Sgamma, B. Spataro, A. Stecchi, A. Stella, S. Tomassini, C. Vaccarezza, M. Zobov (INFN/LNF, Italy), I. Koop, E. Levichev, P. Piminov, D. Shatilov, V. Smaluk (BINP, Russia), S. Bettoni (CERN, Switzerland), K. Ohmi (KEK, Japan), N. Arnaud, D. Breton, P. Roudeau, A. Stocchi, A. Variola, B. F. Viaud (LAL, France), M. Esposito (Rome1 Univ., Italy), E. Paoloni (Pisa Univ., Italy), P. Branchini (Roma3 Univ., Italy), M . Schioppa (INFN-Cosenza, Italy) , P. Valente (INFN-Roma, Italy)

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SuperB is an international enterprise aiming at the construction of a very high luminosity (1036 cm-2 s-1) asymmetric e+e- Flavor Factory, with location at the campus of the University of Rome Tor Vergata, near the INFN Frascati National LaboratoryA heavy flavor factory such as SuperB will be a complimentary window to LHC and ILC The physics studies possible at such a machine will provide a uniquely important source of deeper understanding of the NP found at LHC, and if not found, will bring a sensitivity to seeing signs of NP at even higher energies than LHC to help set the scale of NPA Conceptual Design Report, signed by 85 Institutions was published in March 2007 (arXiv:0709.0451 [hep-ex])

SuperB: a SuperB: a 10103636 cmcm--22 ss--1 1 acceleratoraccelerator

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Power of IntensityPower of IntensityPrecision measurements in the flavour sector are sensitive to New Physics (NP)� Intereference effects in known processes� SM Rare or forbidden decays

NP effects are controlled by� NP scale: Λ� Effective couplings: C

• Different coupling intensity (different interactions)• Differente patterns (e.g. because of simmetries)

With 5-10x1010 bb, cc, ττ pairs (50-100 ab-1) one can:

LHC does not find NP( Λ)• Look for indirect NP signals• Connect them to models• Exclude regions in parameters space

LHC finds NP( Λ)• Determine detailed structure of couplings of NP

• Look for heavier startes• Study NP flavour structure

Some channels, such as the LFV decays of ττττ are unambiguous signals of NP

Courtesy of F. Forti

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Lepton Lepton flavourflavour violation in violation in τ τ decaydecay

SuperB Sensitivity (75 ab-1)

BR

ττττ polarizationBackground reduction

Magnetic moment measurement

Courtesy of F. Forti

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SuperBSuperB DetectorDetectorBabar and Belle designs have proven to be very effective for B-Factory physics� Follow the same ideas for SuperB

detectorA SuperB detector is possible with today’s technology. Main issues:� Machine backgrounds – somewhat

larger than in Babar/Belle� Beam energy asymmetry – a bit smaller� Strong interaction with machine design

Try to reuse parts of Babar as much as possible� Quartz bars of the DIRC� Barrel EMC CsI(Tl) crystal and

mechanical structure� Superconducting coil and flux return

yoke.

Moderate R&D and engineering required� Small beam pipe technology� Thin silicon pixel detector for

first layer� Drift chamber CF mechanical

structure, gas and cell size� Photon detection for DIRC

quartz bars � Forward PID system (TOF or

focusing RICH)� Forward calorimeter crystals

(LSO)� Minos-style scintillator for

Instrumented flux return� Electronics and trigger � Computing – large data amount

Prepare Technical Design Report in 2-3 years

Courtesy of F. Forti

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Detector Layout Detector Layout –– Reuse parts of BabarReuse parts of BabarBASELINE

OPTION

Courtesy of F. Forti

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B-Factories (PEP-II and KEKB) have reached high luminosity (>1034 cm-2 s-1) but, to increase L of ~ 2 ordersof magnitude, bordeline parameters are needed such as:� Very high currents HOM in beam pipe

• overheating, instabilities, power costs• detector backgrounds increase

� Very short bunches RF voltage increases• costs, instabilities

� Smaller damping times Wiggler magnets• costs, instabilities

� Crab cavities for head-on collision• KEKB experience

Accelerator basic concepts (1)Accelerator basic concepts (1)

Difficult and costly operation

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SuperB exploits an alternative approach, with a new IP scheme:� Small beams (ILC-DR like)

• very low emittances, ILC-DR R&D

� Large Piwinsky angle and “crab waist” with a pair of sextupoles/ring (Φ = tg(θ)σz/σx)• interaction region geometry

� Currents comparable to present Factories• lower backgrounds, less HOM and instabilities

Basic concepts (2)Basic concepts (2)

2σσσσz

2σσσσx

θθθθz

x

2σσσσx/θθθθ

2σσσσz*θθθθ

e-e+ββββY

Requires a lot of fine machine tuning

Small collision area: σσσσx/θθθθ

Accelerator basic concepts (2)Accelerator basic concepts (2)

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Ultra-low emittance

Very small β∗ at IPLarge crossing angle

“Crab Waist”transformation

Small collision area

Lower β∗ is possibleNO parasitic crossings

NO x-y-betatron resonances

Thigher focus on beams at IP and a “large” crossing angle (large Piwinski angle) + use a couple of

sextupoles/ring to “twist” the beam waist at the IP

Alreadyproved at DA ΦΦΦΦNE

A new idea for collisions A new idea for collisions

1. P.Raimondi, 2°SuperB Workshop, March 2006

2. P.Raimondi, D.Shatilov, M.Zobov, physics/0702033

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Relatively easier to make small σx with respect toshort σz

Problem of parasitic collisions automatically solved due to higher crossing angle and smaller horizontal beam sizeThere is no need to increase excessively beam current and to decrease the bunch length: �Beam instabilities are less severe�Manageable HOM heating�No coherent synchrotron radiation of short bunches�No excessive power consumption

and...and...

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How it worksHow it worksCrab sextupoles OFF: Waist line is orthogonal to th e axis of other beam

Crab sextupoles ON: Waist moves parallel to the axi s of other beam: maximum particle density in the overlap between bun ches

Plots by E. Paoloni

All particles in both beams collide in the minimum ββββy region, with a net luminosity gain

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0 0.2 0.4 0.6 0.8 1

0

0.2

0.4

0.6

0.8

1

0 0.2 0.4 0.6 0.8 1

0

0.2

0.4

0.6

0.8

1

Typical case (KEKB, DAΦNE):

1. low Piwinski angle Φ < 1

2. βy comparable with σz

Crab Waist On:

1. large Piwinski angle Φ >> 1

2. βy comparable with σx/θ

Much higher luminosity!D.Shatilov’s (BINP), ICFA08 Workshop

Example of xExample of x--y resonance suppressiony resonance suppression

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Comparison of SuperB to SuperComparison of SuperB to Super--KEKBKEKB

0.27/0.30.0004/0.2(x/y)Tune shifts

80 to 9020 to 25MWRF power (AC line)

30. to 0.48.mradCrossing angle (full)

20.3.5x2.0cmββββx*

3.0.22mmββββy*

9.4x4.11.9x1.9ABeam currents

0.5 to 0.81.0 to 2.01036/ cm2/s

Luminosity

3.5x84x7GeVEnergy

Super-KEKBSuperBUnitsParameter

IP beam distributions for KEKB

IP beam distributions for SuperB

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SuperB main featuresSuperB main features

Goal: maximize luminosity while keeping wall power low

2 rings (4x7 GeV) design: flexible but challengingUltra low emittance optics: 7x4 pm vertical emittanceBeam currents: comparable to present Factories Crossing angle and “crab waist” used to maximize luminosity and minimize beam size blow-up�Presently under test at DAΦNE

No “emittance” wigglers used in Phase 1 (save in power)Design based on recycling PEP-II hardware (corresponds to a lot of money)Longitudinal polarization for e- in the HER is included (unique feature)

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SuperSuper--B builds on the Successes of B builds on the Successes of Past AcceleratorsPast Accelerators

PEP-II LER stored beam current: 3.2 A in 1722 bunches (4 nsec) @ 3.1 GeV and 23 nm, with little ECI effect on luminosityLow emittance lattices designed for ILC damping rings, PETRA-3, NSLC-II, and PEP-X (few nm horizontal x few pm vertical)Very low emittance achieved in an ILC test ring: ATFSuccessful crab waist luminosity improvement at DAΦNESuccessful crab cavity tests at KEKB at low currentsSpin manipulation tests in NovosibirskEfficient spin generation with a high current gun and spin transport to the final focus at the SLCSuccessful two beams, asymmetric, interaction regions built by KEKB and PEP-IIContinuous injection works with the detector taking data (KEKBand PEP-II)

J. Seeman, SuperB MiniMAC, LNF July 08

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SuperB design challengesSuperB design challengesBeam beam� high tune shift� strong-strong simulations for large crossing angle� effect of tolerances and component errors

Low emittance� tolerances� achieving vertical emittance� tuning and preserving� vibrations

IR design� 50 nm IP vertical beam size� QD0 design� luminosity backgrounds

Polarization� impact on lattice� depolarization time� impact on beam-beam� continous injection

Lattice� dynamic aperture with crab sextupoles and spin rotator� choice of good working point

All are being addressed in view of the TDR

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Low emittance tuning Low emittance tuning Comparison of achieved beam emittancesComparison of achieved beam emittances

202101978564005ILC-DR

153.228647002882.4SLS*

1800

1800

138

561

1430

C (m)

1043125241.28ATF*

554221.6136997SuperB HER

557222.878284SuperB LER

292 162.758713Diamond*

785946156568Spring-8

γεγεγεγεy(nm)εεεεy (pm)γεγεγεγεx (µµµµm)εεεεx (nm)GammaE (GeV)

Comparison of rings with similar beam energyand ATF, SLS (* achieved)

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PolarizationPolarizationPolarization of one beam is included in SuperB� Either energy beam could be the polarized one� The LER would be less expensive, the HER easier� HER was chosen

Longitudinal polarization times and short beam lifetimes indicate a need to inject vertically polarized electrons.� The plan is to use a polarized e- source similar to the SLAC SLC

source.There are several possible IP spin rotators:� Solenoids look better at present (vertical bends give unwanted vertical

emittance growth)

Expected longitudinal polarization at IP ~ 87%(inj) x 97%(ring) =85%(effective)Polarization section implementation in lattice is in progress

IP

Half IR with spin rotator (Wienands, Wittmer)

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Total length 1800 m

280 m

20 m

Lmag (m) 0.45 5.4

PEP HER - 194

PEP LER 194 -

SBF HER - 130

SBF LER 224 18

SBF Total 224 148

Needed 30 0

Dipoles

Lmag (m) 0.56 0.73 0.43 0.7 0.4

PEP HER 202 82 - - -

PEP LER - - 353 - -

SBF HER 165 108 - 2 2

SBF LER 88 108 165 2 2

SBF Total 253 216 165 4 4

Needed 51* 134 0 4 4

Quads

Available

Needed

All PEP-II magnets can be used, dimensions and fields are in range RF requirements are met by the present PEP-II RF system

Lmag (m) 0.25 0.5

PEP HER/LER 188 -

SBF Total 372 4

Needed 184 4

Sexts

Lattice layout: PEPLattice layout: PEP--II magnets reuseII magnets reuse

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IR layout, siam twins QD0 (R&D)IR layout, siam twins QD0 (R&D)QD0 is common to HER and LER, with axis displaced toward incoming beams to reduce synchrotron radiation fan on SVTDipolar component due to off-axis QD0 induces, as in all crossing angle geometries, an over-bending of low energy out coming particles eventually hitting the pipe or detectorNew QD0 design based on SC “helical-type” windings

M.Sullivan (SLAC)

S. Bettoni (CERN), E. Paoloni (Pisa)

A pm QD0 design also in progress (SLAC)

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SuperB footprint on Tor Vergata siteSuperB footprint on Tor Vergata site

SuperB rings

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Test at DATest at DAΦΦNENEDAΦNE Φ-Factory upgraded for Siddhartaexperiment at end 2007�New collision scheme implemented A new

�Several new components installed machine!�Geometry of rings slightly changed

Commissioning started onDec. ’07. “Simplified”detector installed in March ’08. Final detectorinstalled in Sep. ‘08 and now running

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Luminosity vs ILuminosity vs I++II--

past and presentpast and presentLuminosity in Mayunderestimated by 15-20% for problems of trigger threshold in Bhabha monitor20% reduction of specific L at high currents because of bunch lenghtening (in LPA & CW regime L ∝1/σz) due to machine impedance (effect will be <5% in SuperB)

e- bunch lenght vs bunch current as measuredbefore and after upgrade

Lum

inos

ity (

1028

cm

-2s-

1 )

1

1,5

2

2,5

3

3,5

4

0 5 10 15 20 25 30 35

130kV, new, FWHM/2.36

130kV, old, FWHM/2.36

130kV,upgrade,FWHM/2.36

I [mA]

with ICE

without ICE

upgrade

before

after

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Single bunch luminositySingle bunch luminosity

Luminosity for different bunch patterns No effect seen from parasitic crossingsAchieved single bunch luminosity 4x1030 cm-2 s-1

with 13 mA/bunchMaximum theoretical luminosity without crab sexts 1.5x1030 cm-2 s-1

Ib+Ib- (mA) 2

Lum

inos

ity (

1028

cm

-2s-

1 )

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Luminosity, crab ON/OFFLuminosity, crab ON/OFF

]/[ 212 AscmII

LNL peakb

sp−−

−+=

Luminosity Specific Luminosity95 Bunches

Spe

cific

L (

1028

cm

-2s-

1 /A

2 )

Lum

inos

ity (

1028

cm

-2s-

1 )

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Considerations on the Considerations on the Test of LPA&CWTest of LPA&CW

Overall single bunch luminosity very high: 4x1030 with 13 mA/bunchPeak luminosity record with 95 bunches ≈2.3x1032 cm-2 s-1 (record before upgrade was 1.5x1032 with 110 bunches), limited by positron maximum stored currentSpecific luminosity vs current very close to theoretical expectationsCrab Sextupoles proved very effective for improving the beam-beam

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SuperB is a new machine that can exploit new promising design approaches:� large Piwinski angle scheme will allow for peak luminosity

≥≥≥≥ 1036 cm -2 s-1 well beyond the current state-of-the-art,without a significant increase in beam currents or shorter bunch lengths

� “crab waist” sextupoles used for suppression of dangerous resonances

� low currents with reduced detector and background problems, with affordable operating costs

�polarized electron beam can produce polarized τ leptons, opening an entirely new realm of exploration in lepton flavor physics

The principle of operation is being tested at DAΦNE,where very encouraging results have been achieved

Conclusions (1)Conclusions (1)

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The SuperB design meets the goals requested by the experimenters The baseline lattice, based on the reuse of PEP-II hardware, fits in the Tor Vergata University campus site, near FrascatiA CDR has been positively reviewed by an International Review Committee, chaired by J. Dainton (UK)A Machine Advisory Committee, chaired by J. Dorfan (SLAC), has scrutinized the machine design in July, endorsing the design approach. However more work is needed on specific topics in view of the TDRThe next steps will be to form a team to complete the Technical Design Report by 2010, and…...be included in the CERN Strategy Plan for European infrastructures

Conclusions (2)Conclusions (2)