Photon-Photon Colliders ( Photon-Photon Colliders (  C) Mayda M. Velasco

Idea of  C Based on Compton Backscattering NOT New ( Telnov et.al. ) e −   laser → e −   With circularly polarized  laser (P C = ±1) & polarized e- ( e = 1) ± Example: Optimized as a Higgs Factory  (   H ) >200 fb

What is “New” ? (I) Higgs Discovery in July 2012 Higgs relatively light M H ~125 GeV E ee ~ 160 GeV enough to produce   H

What is “New” ? (II) Development of compact  C starting from e - e - : – Based on already existing accelerator technology – Polarized and low energy e - beam: E e = 80 GeV and ( e = 80%) – Independent of ILC or CLIC – “Low” cost Required laser technology is becoming available. Two options: – Fiber based laser (ICAN) – High power laser developed for fusion program(LLNL)

3 New Designs that will Produce 10K Higgs/year HFiTT: Higgs Factory in Tevatron Tunnel – Fermilab specific SILC: SLC-ILC-Style  Higgs Factory – SLAC specific SAPPHiRE: Small Accelerator for Photon-Photon Higgs production using Recirculating Electrons – Developed at CERN, but can be built elsewhere Detector and beam environment not more difficult than what we are experiencing at the LHC  3 machines in 1: e  e    e −  

e  ( GeV) e  (80 GeV) Fiber Laser (0.351 μm, 5 J, 47.7 kHz) RF (1.3 GHz, 8 sets, 5 cryomodules 1.25 GV /set) RF Tunnel Cross Section (16 permanent magnet beam lines, B = 0.05 – 3.3 kG) HFiTT – Latest Design 2000 m m (8 ft)  collision (125 GeV) E = 80 GeV  = 800 m U = 4.53 GeV/turn I = 0.15 mA x 2 P(rf) = 27 MW m (10 ft) e  ( GeV)

Cost estimate for HFiTT < 1Billion USD With Laser

 2-pass design 1.6 Billion without Laser 1 km radius 45 GeV, 1.5 km or 85 GeV, 3 km 250 m SILC – Presented by Tor Raubenheimer ICFA Higgs Factory Workshop November 14 th, 2012

Scale ~ European XFEL ~ 1 Billion SAPPHiRE – Presented in 2012 at European Strategy Meeting arXiv: arXiv: Energy lost3.89 GeV

Primary Parameters ParameterHFiTTSapphireSILC cms e-e- Energy160 Gev160 GeV Peak  Energy 126 GeV128 GeV130 GeV Bunch charge2e101e105e10 Bunches/train Rep. rate47.7 kHz200 kHz10 Hz Power per beam12.2 MW25 MW7 MW L_ee3.2e342e341e34 L_gg (E  > 0.6 Ecms) 5e33*3.5e332e33 CP from IP1.2 mm1 mm4 mm Laser pulse energy5 J4 J1.2 J Total electric power< = 100 MW

Option #1: Fiber Lasers -- Significant breakthrough Gerard Mourou et al., “The future is fiber accelerators,” Nature Photonics, vol 7, p.258 (April 2013). We need 5 J at ~40kHz! ICAN – International Coherent Amplification Network

LIFE: Option #2: The high peak & high average power lasers needed are also available from  LIFE: Laser Initiated Fusion Energy LIFE beam line : - Pulses at 16 Hz kJ / pulse kW average power - ns pulse width LLBL

Two LIFE based options for SAPPHIRE-like  C Single pass system would have MW average power  10 LIFE beam lines running at 20kHz, each with 100kW average power and interleave pulses to create 200kHz Advantages: – Easier control of photon beam polarization – Eliminate issues with recirculating cavities Disadvantages: – Higher capital cost and energy requirements Recirculating cavity would have 10kW average power  1 LIFE beam line at 200kHz, 0.05J/pulse & 10 kW average power Advantages: – Minimized capital cost and small power requirement Disadvantages: – Phase matching required – Cavity capital cost and operation – Reduced polarization control

Motivation for  C as Higgs Factory and Associated e - e - C and e -  C  C Higgs CP Mixing and Violations e - e - C Running of sin 2  W e  e   e  e  e -  C  - Structure and M W e    W e    W

1 st “run”: e - e - mode ee geometric luminosity: L ee = 2 x cm -2 s s per year: 200 fb -1 or 200,000 pb -1 Moller scattering e - e -  e - e - – E cm = 160 GeV ; Scatt. angle > 5 degree ; P T > 10 GeV for outgoing e - P 1e × P 2e = 0   2981 pb P 1e × P 2e =-1   3237 pb P 1e × P 2e =+1   2728 pb  N ev ~ 6 × 10 8

Precision on sin 2  W at SAPPHIRE Like SLAC-SLC (& LEP) at M Z – A LR based on 150K event –  A LR ~ –  sin 2  W ~ SAPPHiRE at highest  – A LR based on 10 6 event –  A LR ~ –  sin 2  W ~ In addition to precise measurement of running down to 10 GeV  (GeV)  = E cm sqrt{ ½ (1-cos  )}  = scattering angle   Maximum  ~113 GeV

e  e  : Moller Scattering to get running of sin 2  W SAPPHIRE  Complements future lower energy programs

2 nd “run”: e   M W from e     W  and photon structure Mass measurement from W  hadron events Or from energy scan

3 nd “run” :  C Higgs-factory * * ** *

 C a good option for the USA Physics capabilities complementary to LHC 2022 or future ILC because  C will provide: Model independent:  Permil level CP asymmetries can be measured  2% Measurement of   and 10% on  Total - Assuming a 2% uncertainty on Br(H to bb) - Results in a 4% constrain in the Htt Yukawa coupling

Circularly polarized laser Linearly polarized laser  C Higgs-factory to Study CP Violation in Detail

Only with  C == 0 if CP is conserved In s-channel production of Higgs: == +1 (-1) for CP is conserved for A CP-Even (CP-Odd) Higgs If A 1 ≠0, A 2 ≠0 and/or | A 3 | < 1, the Higgs is a mixture of CP-Even and CP-Odd states Possible to search for CP violation in   H  fermions without having to measure their polarization In bb, a ≤1% asymmetry can be measure with 100 fb -1 that is, in 1/2 years arXiv: v2

Conclusion  C is an interesting option – Physics complementary to other programs, but nevertheless unique: Precise measurements of CP-admixture < 1% in Higgs – Laser technology needed to generate  – beam becoming a reality Many more topics that go well beyond Higgs – Already mention: Running of sin 2  W in e  e  – Others  factories: good to study g-2 of the  among other things (e - e -  e - e -    -, e   W  ,    )  (    )> 100 pb