Status of the Super-B factory Design

A Super Flavor Factory, an asymmetric energy e + ecollider with a luminosity of order 10 36 cm -2 s -1 , 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 34 cm -2 s -1 has taught us about the accelerator physics of asymmetric e + ecolliders 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 Super-Flavor collider to also incorporate linear collider techniques. This note describes the parameters of an asymmetric Flavor-Factory collider at a luminosity of order 10 36 cm -2 s -1 at the Υ(4S) resonance and perhaps about 10 35 cm -2 s -1 at the τ production threshold. Such a collider would produce an integrated luminosity of about 10,000 fb -1 (10 ab -1 ) in a running year (10 7 sec) at the Υ(4S) resonance.

In the short time alloted for this talk it is not possible to review all the physics opportunities offered by a B Factory. I focus on the physics of CP Violation and the resulting tests of the Standard Model. In this talk a"B Factory" in will be taken to mean an asymmetric e+e-collider running at the 'Yf(4S) with a luminosity of 3 x 1O33 or greater. The decay of the Y(4S) is essentially 50% to B+B-and 50% to go@, so such a facility provides a copious and clean source of B mesons. The purpose of the asymmetric configuration is to produce the B's with high enough laboratory momenta that the two decays are typically well separated in space. The aim is to be able to reconstruct the two B-decay vertices independently and to measure their separation. This then allows the measurement of time-dependent correlated decay proba.bilities, which we shall see are essential for the extraction of CP violation physics. In the past couple of years groups at SLAC ') and Cornell') a.s well as here at KEK and in Europe have refined and advanced the a.ccelera.tor physics questions associated with such a machine and .now have formulated detailed designs. 1 am not competent to judge the feasability of these designs but I am told that it is no longer just a theorists dream that such a machine could be built, provided that somewhere the funding is sufficient for the job. I fervently hope this will occur, beca.use I think the physics opportunities for such a machine are extremely rich.

2009

The SuperB project aims at the construction of an asymmetric very high luminosity B-Factory on the Frascati/Tor Vergata (Italy) area, providing a uniquely sensitive probe of New Physics in the flavour sector of the Standard Model. The luminosity goal of 10 36 cm-2 s-1 can be reached with a new collision scheme with "large Piwinski angle" (LPA) and the use of "crab waist sextupoles" (CW) [1]. A LPA&CW Interaction Region (IR) has been successfully tested at the DA NE-Factory at LNF-Frascati in 2008 [2]. The LPA&CW scheme, together with very low *, will allow for operation with relatively low beam currents and reasonable bunch length, comparable to those of PEP-II and KEKB. In the High Energy Ring (HER), two spin rotators will bring longitudinally polarized beams into collision at the IP. The lattice has been designed with a very low intrinsic emittance and is quite compact, less than 2 km long. The tight focusing requires the final doublet quadrupoles to be very close to the IP and very compact. A Conceptual Design Report was published in March 2007 [3], and beam dynamics and collective effects R&D studies are in progress in order to publish a Technical Design Report by the end of 2010.

Proceedings of the 2005 Particle Accelerator Conference, 2005

PEP-II is an e + easymmetric B-Factory Collider located at SLAC operating at the Upsilon 4S resonance (3.1 GeV x 9 GeV). It has reached a luminosity of 9.21x10 33 /cm 2 /s and has delivered an integrated luminosity of 710 pb-1 in one day. PEP-II has delivered, over the past six years, an integrated luminosity to the BaBar detector of over 262 fb-1. PEP-II operates in continuous injection mode for both beams boosting the integrated luminosity. The peak positron current has reached 2.45 A in 1588 bunches. Steady progress is being made in reaching higher luminosity. The goal over the next several years is to reach a luminosity of 2.1x10 34 /cm 2 /s. The accelerator physics issues being addressed in PEP-II to reach this goal include the electron cloud instability, beam-beam effects, parasitic beam-beam effects, high RF beam loading, shorter bunches, lower β y * interaction region operation, and coupling control. Figure 1 shows the PEP-II tunnel.

Proceedings of XXIst International Europhysics Conference on High Energy Physics — PoS(EPS-HEP2011), 2012

Progress of Theoretical and Experimental Physics, 2013

The SuperKEKB project requires a positron and electron collider with a peak luminosity of 8 × 10 35 cm −2 s −1. This luminosity is 40 times that of the KEKB B-factory, which operated for 11 years up to 2010. SuperKEKB is an asymmetry-energy and double-ring collider; the beam energy of the positron (LER) is 4 GeV and that of the electron (HER) is 7 GeV. An extremely small beta function at the interaction point (IP) and a low emittance are necessary. In addition, in order to achieve the target luminosity, a large horizontal crossing angle between two colliding beams is adopted, as is a bunch length much longer than the beta function at the IP. This method is called the "nano-beam scheme". The beam-beam parameter is assumed to be similar to KEKB, the beta function at the IP is 1/20, and the beam currents are twice those of KEKB in the nano-beam scheme. Consequently, the luminosity gain of 40 with respect to KEKB can be obtained.

European Physical Journal - Special Topics, 2019

Particle physics has arrived at an important moment of its history. The discovery of the Higgs boson, with a mass of 125 GeV, completes the matrix of particles and interactions that has constituted the “Standard Model” for several decades. This model is a consistent and predictive theory, which has so far proven successful at describing all phenomena accessible to collider experiments. However, several experimental facts do require the extension of the Standard Model and explanations are needed for observations such as the abundance of matter over antimatter, the striking evidence for dark matter and the non-zero neutrino masses. Theoretical issues such as the hierarchy problem, and, more in general, the dynamical origin of the Higgs mechanism, do likewise point to the existence of physics beyond the Standard Model. This report contains the description of a novel research infrastructure based on a high-energy hadron collider, which extends the current energy frontier by almost a factor 2 (27 TeV collision energy) and an integrated luminosity of at least a factor of 3 larger than the HL-LHC. In connection with four experimental detectors, this infrastructure will deepen our understanding of the origin of the electroweak symmetry breaking, allow a first measurement of the Higgs self-coupling, double the HL-LHC discovery reach and allow for in-depth studies of new physics signals arising from future LHC measurements. This collider would directly produce particles at significant rates at scales up to 12 TeV. The project re-uses the existing LHC underground infrastructure and large parts of the injector chain at CERN. This particle collider would succeed the HL-LHC directly and serve the world-wide physics community for about 20 years beyond the middle of the 21st century. The European Strategy for Particle Physics (ESPP) update 2013 stated “To stay at the forefront of particle physics, Europe needs to be in a position to propose an ambitious post-LHC accelerator project at CERN by the time of the next Strategy update”. The FCC study has implemented the ESPP recommendation by developing a vision for an “accelerator project in a global context”. This document describes the detailed design and preparation of a construction project for a post-LHC circular high-energy hadron collider “in collaboration with national institutes, laboratories and universities worldwide”, and enhanced by a strong participation of industrial partners. Now, a coordinated preparation effort can be based on a core of an ever-growing consortium of already more than 135 institutes worldwide. The technology for constructing a High-Energy LHC can be brought to the technology readiness level required for construction within the coming ten years through a committed and focused R&D; programme. The concept comprises a power-saving, low-temperature superconducting magnet system based on an evolution of the Nb3Sn technology pioneered at the HL-LHC, an energy-efficient cryogenic refrigeration infrastructure based on a neon-helium (Nelium) light gas mixture, a high-reliability and low loss cryogen distribution infrastructure based on Invar, high-power distributed beam transfer using superconducting elements and local magnet energy recovery and re-use technologies that are already gradually introduced at other CERN accelerators. Re-use of the LHC underground civil infrastructure worth about 500 million CHF at the time of its construction, extension of the surface sites and use of the existing injector chain that also serve for a concurrently running physics programme are levers to come to a sustainable research infrastructure at the energy frontier. Strategic R&D; for HE-LHC aims at minimising construction cost and energy consumption, while maximising the socio-economic impact. It needs to mitigate technology-related risks and ensure that industry can benefit from an acceptable economic utility. Concerning the implementation, a preparatory phase of about eight years is both necessary and adequate to establish the project governance and organisation structures, to build the international machine and experiment consortia, to develop a territorial implantation plan considering the constraints emerging from using the existing infrastructure and the host states’ requirements, optimising the use of land, resources and preparing the construction project. Such a large-scale, international fundamental research infrastructure, tightly involving industrial partners and providing training at all education levels, will be a strong motor of economic and societal development in all participating nations. The FCC study has implemented a set of actions towards a coherent vision for the world-wide high-energy and particle physics community, providing a collaborative framework for topically complementary and geographically well-balanced contributions. This conceptual design report lays the foundation for a subsequent infrastructure preparatory and technical design phase.

Particle Accelerator, IEEE Conference, 2005

Parameters are being studied for a high luminosity e+e-collider operating at the Upsilon 4S that would deliver a luminosity in the range of 7 to 10 x 1035/cm2/s. Particle physics studies dictate that a much higher luminosity collider than the present B-Factory accelerators will be needed to answer future new key physics questions. The success of the present B-Factories, PEP-II

2007 IEEE Particle Accelerator Conference (PAC), 2007

Experimental studies of fundamental structure of nucleons require an electron-ion collider of a center-ofmass energy up to 90 GeV at luminosity up to 10 35 cm -2 s -1 with both beams polarized. A CEBAF-based collider of 9 GeV electrons/positrons and 225 GeV ions is envisioned to meet this science need and as a next step for CEBAF after the planned 12 GeV energy upgrade of the fixed target program. A ring-ring scheme of this collider developed recently takes advantage of the existing polarized electron CW beam from the CEBAF and a green-field design of an ion complex with electron cooling. We present a conceptual design and report design studies of this high-luminosity collider.

2019

Centre d'études et d'expertise sur les risques, l'environnement, la mobilité et l'aménagement