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Higgs Factories based on: - LEP3 circular e+e- machine
- SAPPHIRE gg collider
Mayda M. VelascoNorthwestern University
BNL Seminar -- Jan. 17, 2013
“Rich” mass regionAlready measuring its
characteristics
• Mass from gg plus ZZ 4L*– M = 125.8 ± 0.4 (stat) ± 0.4 (syst)
• Parity– 0+ : Scalar hypothesis consistent at a
0.6s level*– 0- : Pseudo scalar hypothesis excluded
at 2.5s level*
• Coupling– To both bosons and fermions
• Spin– No sensitivity yet to separate
between Spin 0 & Spin 2 However, some argue that the
observed rate is an indication that is not a spin 2 object
Access to Higgs partial widths of to Bosons and Fermions
* CMS based… Similar at ATLAS
So, what is next?Low Energy Higgs Factory Concepts
Some examples of measurements needed after the LHC:
Today… discussed two types of factories that could do the job!
• Continue to characterize the state– Coupling to the top quark– Self couplings– Total width
• Need to evaluate (new physics) loop induced effects – Hgg, Hgg, HZg– Precision electroweak measurements– Precision mass measurements (W, Z, top,
...)
• Need to determine the (tree level) structure of the theory – Invisible Higgs decays, Exotic Higgs decays?– CP mixing and violations?
LEP3 and TLEP -- e+e- ring
PSB PS (0.6 km)SPS (6.9 km) LHC (26.7 km)
LEP3(e+e-, 240 GeV c.m.)
In the LHC tunnel (LEP3) or a new tunnel (TLEP)
• Instantaneous luminosity larger than 1034/s/cm2 at maximum energyLarger at smaller energiesDelivered in 2 or 4 interaction points ATLAS and CMS in LEP3
TLEP (80 km, e+e-
~350 GeV c.m.)
VHE-LHC ( later… pp, 100 TeV c.m.)
The two options
• Installation in the LHC tunnel “LEP3” inexpensive (<0.1 x LC) tunnel exists reusing ATLAS and CMS detectors reusing LHC cryoplants interference with LHC and HL-LHC
• New larger tunnel “TLEP” higher energy reach, (5-10)x higher luminosity decoupled from LHC/HL-LHC operation & construction tunnel can later serve for HE-LHC (factor 3 in energy from tunnel alone) with LHC remaining as injector (4-5)x more expensive (new tunnel, cryoplants, detectors)
LHC tunnel cross section with space reserved for a future lepton machine like LEP3 [blue box above the LHC magnet] and with the presently proposed location of the LHeC ring [red]
Putting LEP3 into the LHC tunnel?
«Pre-Feasibility Study for an 80-km tunnel at CERN»John Osborne and Caroline Waaijer, CERN, ARUP & GADZ, submitted to ESPG
TLEP tunnel in the Geneva area – “best” option
LEP3 and TLEP
LEP3 TLEPcircumference 26.7 km 80 kmmax beam energy 120 GeV 175 GeVmax no. of IPs 4 4 Lum. 350 GeV c.m. - 0.7x1034 cm-2s-1 Lum. 240 GeV c.m. 1034 cm-2s-1 5x1034 cm-2s-1 Lum. 160 GeV c.m. 5x1034 cm-2s-1 2.5x1035 cm-2s-1 Lum. 90 GeV c.m. 2x1035 cm-2s-1 1036 cm-2s-1
ee tt
ee ZH
ee WW
ee Z
Basic parameters:
Beam Lifetime
• LEP2: • beam lifetime ~ 6 h • dominated by radiative Bhabha scattering with cross section s ~
0.215 barn
• LEP3 with L~1034 cm−2s−1 at each of several IPs:tbeam,LEP3~18 minutes from rad. Bhabha scattering
→ solution: top-up injection
Beam lifetime also limited due to beamstrahlung, but can be compensated for using:(1) large momentum acceptance (h ≥ 3%), and/or(2) flat(ter) beams and/or (3) fast replenishing
arc optics• same as for LHeC: ex,LHeC<1/3 ex,LEP1.5 at equal beam energy,• optical structure compatible with present LHC machine (not optimum!)• small momentum compaction (short bunch length)• assume ey/ex ~5x10-3 similar to LEP (ultimate limit ey ~ 1 fm from opening angle)
RF • RF frequency 1.3 GHz or 700 MHz• ILC/ESS-type RF cavities high gradient (20 MV/m assumed, 2.5 times LEP gradient)• total RF length for LEP3 at 120 GeV similar to LEP at 104.5 GeV• short bunch length (small b*
y) • cryo power ≤LHC
synchrotron radiation • energy loss / turn: Eloss[GeV]=88.5×10−6 (Eb[GeV])4 /ρ[m]. • higher energy loss than necessary • arc dipole field = 0.153 T• compact magnet • critical photon energy = 1.4 MeV• 50 MW/beam (total wall plug power ~200 MW ~ LHC complex)→4x1012 e±/beam
Other LEP3 parameters
LEP3 as Higgs FactoryHiggs-strahlung is main production process: HZZ coupling observed at the LHC Vector boson fusion give small contribution Reasonable background level
MH=125 GeV
TLEP Physics program
Same as LEP3…• Less synchrotron radiation
and …– five times more luminosity at
√s = 240 GeV– 2 to 5 times more luminosity
at √s = mZ or 2mW
• Top physics at √s = 350 GeV– precision top mass
measurement
Beamstrahlung much more benign
than for linear collider;
LEP3/TLEP are clean machines
Comment: Beamstrahlung effect at LEP3 much smaller than for ILC
Only discussed: LEP3 and TLEP (& ILC), but many more options for circular e+e-
Higgs factories are becomingpopular around the world
LEP3 2011
SuperTristan 2012LEP3 on LI, 2012
LEP3 in Texas, 2012
FNAL site filler, 2012West Coast design, 2012
Chinese Higgs Factory, 2012
UNK Higgs Factory, 2012
Combining photon science & particle physics!
gg collider based on e-e-
glaser: Pulses of a several Joules with a l~350nm (3.53 eV) for Ee- ~ 80 GeV
Compton scattering: e− glaser → e−g
can transfer 80% of e- energy to g
e-e-, e-g and gg colliders
– Higgs produced in s-channel (low ee CoM)
– Starts from e-e- therefore, both beam can be highly polarized
– Laser or FEL needed to generate high g-beam (e− glaser → e−g) are now available• Opportunity to work with technology, that is of interest to other fields of basic
science and industry
– Compact machine: less that 10 Km in diameter• Fits in various national labs
– “Low cost”
Only with ggC
== 0 if CP is conserved
In s-channel production of Higgs:
== +1 (-1) for CP is conserved forA CP-Even (CP-Odd) Higgs
If A1≠0, A2≠0 and/or |A3| < 1, the Higgs is a mixture of CP-Even and CP-Odd states
Possible to search for CP violation in gg 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:0705.1089v2
This is why we should consider a low energy gg collider, like SAPPHIRE,
as a Higgs Factory
Search for the unexpected properties of the Higgs in a model independent way… That is,
Higgs CP Mixing and Violations
CP asymmetries at the 1% level or better will be accessible with current designs by taking
advantage of both linear and circular polarization
SAPPHiRE
SAPPHiRE: Small Accelerator for Photon-Photon Higgs production using Recirculating Electrons
Scale ~ European XFEL,About 20k Higgs per year
Energy loss of multiple passes
beam energy [ GeV]
DEarc [GeV] DsE [MeV]
10 0.0006 0.03820 0.009 0.4330 0.05 1.740 0.15 5.050 0.36 1060 0.75 2070 1.39 3580 1.19 27
total 3.89 57 (0.071%)
D
Prototype arc magnetsLHeC dipole models(BINP & CERN)
eRHIC dipole model (BNL)
5 mm gapmax. field 0.43 T (30 GeV)
25 mm gapmax. field 0.264 T (60 GeV)
SAPPHiRE symbol valuetotal electric power P 100 MWbeam energy E 80 GeVbeam polarization Pe 0.80bunch population Nb 1010
repetition rate frep 200 kHzbunch length sz 30 mmcrossing angle qc ≥20 mradnormalized horizontal/vert. emittance gex,y 5,0.5 mmhorizontal IP beta function bx* 5 mmvertical IP beta function by* 0.1 mmhorizontal rms IP spot size sx* 400 nmvertical rms IP spot size sy* 18 nmhorizontal rms CP spot size sx
CP 400 nmvertical rms CP spot size sy
CP 440 nme-e- geometric luminosity Lee 2x1034 cm-2s-1
Luminosity spectra for SAPPHiRE as functions of ECM(gg), for 3 possible normalized distances r≡lCP-IP/(gsy*) (left) and different polarizations of in-coming e- & g (right)
SAPPHiRE gg luminosity
5 Linacs
IPIP
2 Linacs
Top Energy 80 GeV 80 GeV
Turns 3 4
Magnet ρ 644.75 m 706.65 m
Linacs (5) 5.59GeV 4.23GeV
δp/p 6.99x10-4 7.2x10-4
ϵnx Growth 1.7μm 1.8μm
Top Energy 80 GeV 80 GeV
Turns 4 5
Avg. Mag. ρ 661.9 m 701.1 m
Linacs (2) 10.68GeV 8.64GeV
δp/p 8.84x10-4 8.95x10-4
ϵnx Growth 2.8μm 2.85μm
1) 2)
Possible Configurations at FNAL
Possible Configurations at JLAB
85 GeV Electron energyγ c.o.m. 141 GeV
103 GeV Electron energyγ c.o.m. 170 GeV
Edward Nissen
Town Hall meeting Dec 19 2011
Ex. of physics program relevant to our understanding of Higgs that will be
accessible with SAPPHIRE
• e-e- ---> sin2 qW (running)
• e- g ---> MW
• gg to H– G gg gttH
– GTotal
– CP mixing and violation in a model independent way from both gHff and gHVV
e-e-: Moller Scattering to get running of sin2 qW
> mbarn
Should we aim at higher ee Ecm?Currently 160 GeV
%2 Measurement of Ggg
%10 Measurement of GTotal
Assuming that we know DBr(h bb) ~2%
Only with ggC
4% constraint in ttHYukawa coupling
Low energy gg colliders
• This machine will be crucial to study the CP mixing and violation in the Higgs sector
• Using the e-e- component of the beam, we could not only make precise measurements of the running of sin2qW, but also:– Majorana neutrinos by searching for e-e- W-W-
• Many more physics topics that go well beyond Higgs– Tau Tau factory … good to study g-2 of the t lepton– Quark structure of the photon, etc.
Conclusions
• LEP3 and SAPPHIRE may some of the cheapest possible option to study the Higgs (cost ~1B scale), feasible, ee component “off the shelf”, but perhaps not easy
• TLEP is more expensive (~5 BEuro?), but clearly superior in terms of energy & luminosity, and extendable towards VHE-LHC, preparing ≥50 years of exciting e+e-, pp, ep/A physics at highest energies
• SAPPHiRE matches infrastructure, expertise & sites of many HEP or former or future HEP laboratories (JLAB, SLAC, KEK, FNAL, BNL, DESY,…)
SAPPHiRE DAY 19 February 20131. Physics case: Theory, John Ellis / King’s College2. Physics case: Experiment, Mayda Velasco / Northwestern U. 3. Machine concept & options – Frank Zimmermann / CERN4. Luminosity calculations (?) – Marco Zanetti / MIT Or Daniel Schulte / CERN5. Commercial lasers & future extrapolation - Laura Corner / JAI 6. R&D status for gamma-ray and X-ray generation based on Compton scattering at KEK, Junji
Urakawa / KEK7. Feedback R&D for Optical Cavity, Hiroshima U.8. Compton collision scheme of the EGAMMAS Proposal for ELI-NP, Luca Serafini /INFN-Milano 9. Optical cavity & IR design for gamma-gamma collider , Klaus Moenig/DESY 10. High finesse multi-mirror optical cavity w feedback, Fabian Zomer/LAL 11. LAL Compton collisions and Thom-X project, Alessandro Variola/LAL 12. Duke FEL-Compton scheme and outlook, Vladimir Litvinenko/BNL 13. High average power femtosecond laser technology, Marc Hanna/Institut d'Optique Palaiseau14. Current status and future of high-power ultrafast industrial lasers, Yoann Zaouter/Amplitude
Systemes15. Extrapolating Current Laser Technology for a SAPPHiRE Laser System, Jeff Gronberg/LLNL16. Gamma-gamma & Compton studies at FACET-2, Vitaly Yakimenko/SLAC
Self-generated FEL g beams (instead of laser)?
opticalcavity mirrors
wigglerconverting somee- energy into photons (l≈350 nm)
e- (80 GeV)
e- (80 GeV)
Comptonconversionpoint
gg IP
e- bende- bend
example: lu=200 cm, B=0.625 T, Lu=100 m, U0,SR=0.16 GeV, 0.1%Pbeam≈25 kW
“intracavity powers at MW levels are perfectly reasonable” – D. Douglas, 23 August 2012
scheme developed with Z. Huang
Source: Fiber lasers and amplifiers: an ultrafast performance evolution, Jens Limpert, Thomas Schreiber, and Andreas Tünnermann, Applied Optics, Vol. 49, No. 25 (2010)
power evolution of cw double-cladfiber lasers with diffraction limited beam quality over the past decade:factor 100 increase!
laser progress: example fiber lasers
LAL MightyLaser experiment at KEK-ATFnon-planar high finesse four mirror Fabry-Perot cavity;first Compton collisions observed in October 2010
I. Chaikovska, N. Delerue, A. Variola, F. Zomer et al
Comparison of measured and simulated gamma-ray energy spectra from Compton scattering
Gamma ray spectrum for different FPC stored laser power
Vacuum vessel for Fabry-Perot cavity installed at ATFOptical system used for laser power amplification and to inject laser into FPC Plan:
improve laserand FPC mirrors& gain several orders
I. Chaikovska, PhD thesis to be published