Design of an Asymmetric Super-b Factory*

A Super Flavor Factory, an asymmetric energy ee collider with a luminosity of order 10 cms, can provide a sensitive probe of new physics in the flavor sector of the Standard Model. The success of the PEP-II and KEKB asymmetric colliders [1,2] in producing unprecedented luminosity above 10 cms has taught us about the accelerator physics of asymmetric ee colliders in a new parameter regime. Furthermore, the success of the SLAC Linear Collider [3] and the subsequent work on the International Linear Collider [4] allow a new SuperFlavor collider to also incorporate linear collider techniques. This note describes the parameters of an asymmetric Flavor-Factory collider at a luminosity of order 10 cmsat the Υ(4S) resonance and perhaps about 10 cms at the τ production threshold. Such a collider would produce an integrated luminosity of about 10,000 fb (10 ab) in a running year (10 sec) at the Υ(4S) resonance. 1 DESIGN FROM PAST SUCCESSES The construction and operation of modern multi-bunch ee colliders have brought about many advances in accelerator physics in the area of high currents, complex interaction regions, high beam-beam tune shifts, high power RF systems, controlled beam instabilities, rapid injection rates, and reliable uptimes (~95%): 1) Colliders with asymmetric energies can work. 2) Beam-beam energy transparency conditions are weak. 3) Interaction regions with two energies can work. 4) IR backgrounds can be handled successfully. 5) High current RF systems can be operated (3 A x1.8 A). 6) Beam-beam parameters can reach 0.06 to 0.09. 7) Injection rates are good and continuous injection is done in production. 8) The electron cloud effect (ECI) can be managed. 9) Bunch-by-bunch feedbacks at 4 nsec spacing work. Lessons learned from SLC and subsequent linear collider studies (for ILC) and experiments (FFTB, ATF, ATF2) have also shown new successful concepts: A) Small horizontal and vertical emittances can be produced in a damping ring with a short damping time. B) Very small beam spot sizes and beta functions can be achieved at the interaction region. C) Bunch length compression can be performed. *Supported by US DOE contract DE-AC02-76SF00515. [email protected] 2 LUMINOSITY The design of a 10 cms ee collider combines extensions of the design of the present B Factories and linear collider concepts to allow improved beam parameters to be achieved. The luminosity L in an ee collider is given by the expression