A possibility of ring collider for Higgs factory 13 Feb. 2012 K. Oide (KEK) Inspired by A. Blondel and F. Zimmermann, A High Luminosity e+e- Collider in the LHC tunnel to study the Higgs Boson, V2.1 - V2.7, arxiv:1112.2518v1 [hep- ex], 24 Dec 2011.
Motivations If the Higgs mass is below 130 GeV, an e+e- ring collider may have merits as a Higgs factory: Based on existing technologies which have been proven for 40 years by a number of colliders. The machine will be simple enough, and the operation will be easy and straightforward. The design luminosity will be quickly achieved, for instance after 6 months commissioning. Cheaper construction / operation costs than linear machines. S. Yamashita via A. Blondel and F. Zimmermann
Parameters Example TRISTAN KEKB LEP2 LEP3 DLEP 40 60 Beam Energy Circumference Beam Current / beam Bunches / beam β* x / y Emittances x / y Bunch length Beam-beam parameters Radiation loss / turn RF Voltage RF frequency Total SR Power Luminosity / IP 32 8 / 3.5 105 120 120 120 120 GeV 3 3 27 27 53 40 60 km 7 1400 / 1700 4 7.2 14.4 8.6 8.6 ma 2 1600 4 3 60 12 18 2000 / 40 1200 / 6 1500 / 65 150 / 1.2 200 / 2 80 / 2.5 80 / 2.5 mm 18 / 0.1 48 / 0.25 20 / 0.15 5 / 0.05 23.3 / 0.09 24.6 / 0.09 nm 10 6 3 3 1.5 3 3 mm 0.02 0.025 0.05 0.09 0.025 0.065 0.126 0.13 0.1 0.1 0.05 0.156 0.045 0.155 300 4 / 2 2750 6900 3470 3420 2150 MV 400 10 / 5 3640 9000 4600 5000 3300 MV 508 509 352 1300 1300 1300 1300 MHz 4.2 5.6 / 3.4 22 100 100 59 37 MW 0.04 21 0.13 13 16 10 10 /nb/s
Injection / top up Just follow the LEP3 s scheme (Figure). Use a 10 GeV injector instead of SPS in our case. A. Blondel and F. Zimmermann
Lattice (without IP, etc.)
40 八郷植物センター 薬王院 12.3 km KEK
Costs (very very very rough) Tunnel RF Magnet Beam pipe Synchrotron Others Detector CF 40 60 1600 2400 0.04 / m 450 300 5 / MW 50 60 0.04 / magnet 80 120 0.002 / m 150 200? 100 100? 200 200 1 IP? 100 100? Total construction site power* cost / year 2730 3480 83 63 4,000h 15 yen / kwh *Assuming site power SR power *1.5 + 50 MW
More Aggressive Choices Nano beam scheme as applied at SuperKEKB & SuperB allows βy* shorter than the bunch length. ECM = 400 GeV to detect the self coupling of Higgs. L = 5 x 10 34 with σ = 0.07 fb generates 35 ZHH events per year (10 7 sec). G. Belanger, et al
Parameters Example (2) 40-Nano 60-Nano 80-Nano Beam Energy Circumference Beam Current / beam Bunches / beam β* x / y Emittances x / y Bunch length Beam-beam parameters Radiation loss / turn RF Voltage RF frequency Total SR Power Luminosity / IP 200 200 200 GeV 40 60 80 km 1.5 2 3 ma 1 1 2 20 / 0.2 30 / 0.32 25 / 0.2 mm 2.0 / 0.011 3.2 / 0.017 3.2 / 0.017 nm 1.3 1.4 1.7 mm 0.017 0.160 0.017 0.155 0.015 0.160 33900 18500 13060 MV 35000 21000 15000 MV 1300 1300 1300 MHz 102 74 78 MW 40 52 77 /nb/s
Parameters Example (3) 40-Nano 60-Nano Beam Energy Circumference Beam Current / beam Bunches / beam β* x / y Emittances x / y Bunch length Beam-beam parameters Radiation loss / turn RF Voltage RF frequency Total SR Power Luminosity / IP 120 120 GeV 40 60 km 1 0.85 ma 1 1 26 / 0.25 30 / 0.25 mm 3.0 / 0.011 3.0 / 0.011 nm 1.9 1.9 mm 0.014 0.160 0.013 0.160 3420 2150 MV 5000 3300 MV 1300 1300 MHz 6.84 3.655 MW 12 10 /nb/s
Costs (very very very rough) Tunnel RF Magnet Beam pipe Synchrotron Others Detector CF Total construction site power* cost / year 40-Nano 60-Nano 80-Nano 1600 2400 3200 0.04 / m 750 560 585 5 / MW 240 200 200 0.04 / magnet 80 120 160 0.002 / m 200 250 300? 100 120 150? 200 200 200 1 IP? 100 150 200? 3270 4000 4995 122 97 100 4,000h 15 yen / kwh *Assuming site power SR power *1.5 + 50 MW
Even More Aggressive... ECM = 500 GeV to detect the Higgs-top coupling. L = 1 x 10 34 with σ = 0.3 fb generates 30 tth events per year (10 7 sec). ttbar-higgs 800 GeV 600 GeV 500 GeV e + e t t H Cross section (fb) 3 2.5 2 1.5 1 0.5 0 120 140 150 200 250 300 350 Higgs Mass (GeV) J. Butler
Parameters Example (4) Beam Energy Circumference 80-Nano 250 GeV 80 km Tunnel 80-Nano 3200 0.04 / m Beam Current / beam 1.4 ma RF 680 5 / MW Bunches / beam 2 Magnet 200 0.04 / magnet β* x / y 34 / 0.26 mm Beam pipe 160 0.002 / m Emittances x / y Bunch length Beam-beam parameters Radiation loss / turn 3.4 / 0.013 nm 1.9 mm 0.018 0.140 32450 MV Synchrotron Others Detector CF 300? 150? 200 1 IP? 200? RF Voltage RF frequency Total SR Power 34700 MV 1300 MHz 90 MW Total construction site power* cost / year 5090 111 4,000h 15 yen / kwh Luminosity / IP 20 /nb/s *Assuming site power SR power *1.5 + 50 MW
Parameters Example (5) Beam Energy Circumference 40-Nano 120 GeV 40 km Tunnel 80-Nano 1600 0.04 / m Beam Current / beam 1 ma RF 450 5 / MW Bunches / beam 1 Magnet 50 0.04 / magnet β* x / y 26 / 0.25 mm Beam pipe 80 0.002 / m Emittances x / y Bunch length Beam-beam parameters Radiation loss / turn 3.0 / 0.011 nm 1.9 mm 0.014 0.160 3420 MV Synchrotron Others Detector CF 150? 100? 200 1 IP? 100? RF Voltage RF frequency Total SR Power 5000 MV 1300 MHz 6.84 MW Total construction site power* cost / year 2730 31 4,000h 15 yen / kwh Luminosity / IP 12 /nb/s *Assuming site power SR power *1.5 + 50 MW
Parameters Example (6) Beam Energy Circumference 60-Nano 200 GeV 60 km Tunnel 80-Nano 2400 0.04 / m Beam Current / beam 2 ma RF 560 5 / MW Bunches / beam 1 Magnet 200 0.04 / magnet β* x / y 30 / 0.32 mm Beam pipe 120 0.002 / m Emittances x / y Bunch length Beam-beam parameters Radiation loss / turn 3.2 / 0.017 nm 1.4 mm 0.017 0.155 18500 MV Synchrotron Others Detector CF 250? 120? 200 1 IP? 150? RF Voltage RF frequency Total SR Power 21000 MV 1300 MHz 74 MW Total construction site power* cost / year 4000 97 4,000h 15 yen / kwh Luminosity / IP 52 /nb/s *Assuming site power SR power *1.5 + 50 MW
Ring or Linear? Technology: Matured & Experienced Ring >>> Linear Robustness on Luminosity Ring >> Linear Remember SLC. Beamstrahlung-free Ring Linear? Needs detailed calculation Electron Cloud-free Ring >>> Linear Sources Ring >> Linear Polarization Linear > Ring ΥΥ option Linear >>> Ring No solution known for ring. Extendability Ring: Hadron Collider Linear: Higher Energy by a different scheme Both require significant investment.
Ring or Linear? Construction Site Power (MW) ECM (GeV) Ring Linear ECM (GeV) Ring Linear 240 2700 4300 240 60 146 400 4000 5900 400 111 210 500 5090 6900 500 185 250 7000 250 6000 200 5000 4000 150 3000 100 2000 50 1000 0 0 240 400 ECM (GeV) 500 Ring 240 Linear 400 ECM (GeV) 500