Transcript LHeC に向けて
LHeC に向けて protons protons antiprotons protons electrons? ＫＥＫ 徳宿克夫 2008年1月12日 12/Jan/2008 1 HERA: (27.5 GeV e vs 920GeV p) nuclei LHeC (70GeV e vs 7000GeV p) proton LHeC 12/Jan/2008 2 歴史 • “Deep Inelastic Electron-Nucleon Scattering at the LHC” J.B. Dainton, M. Klein, P. Newman, E. Perez, F. Willeke JINST 1 (2006) P10001 • DIS2006 (つくば） ： J. Daintonのトーク • 2006 Ａｄｖｉｓｏｒｙ Ｃｏｍｍｉｔｔｅｅ が組織 • 2007 Ｓｔｅｅｒｉｎｇ Ｇｒｏｕｐ結成 10月26日 初会合 • 2007年11月30日 Open ECFA ミーティングでの発表 （Ｍ． Ｋｌｅｉｎ） ECFA, CERNのサポートが得られる。 • ＷＧ結成に向けて、Ｃｏｎｖｅｎｏｒの人選中。 2008年9月にCERN近辺で ワークショップ。 • 2009年末に ＣＤＲ ep と pp が同時に実験できるオプション以外はない。 電子加速器を建設する機会はLHCアップグレードのときのみ 12/Jan/2008 3 Inclusive Kinematics for 70 GeV x 7 TeV s 1.4 TeV W 1.4 TeV 7 x 10 at New physics, distance Q2 1 GeV2 scales few . 10-20 m High precision partons in LHC plateau High Density Matter 12/Jan/2008 Low x parton dynamics Large x partons • High mass (Q2) frontier • Q2 lever-arm at moderate x • Low x (high W) frontier 4 ●たとえば、leptoquark レプトンとクォークがあるなら、その両方の 性質をもった粒子もあっていいのでは？ LHC 対生成 LHeC もともとある クォークとレプトンから作れる Re + resonance LHCで発見された後、LHeCで狙いを定めて精密測定 12/Jan/2008 5 対生成の断面積は、QCD： αs とマスで決まる。 Eqだと断面積はそのe-q-LQ結合の強さに よる。 Sensitivityは残念ながら、LHCよりそう 優れているわけではない。 12/Jan/2008 6 しかし、見つかったあとで、LQの 性質を調べるのには LHeCは 非常に有効 F = +1 + e, q e+ _ q or q ? Asymmetry F = -1 LHC: single prod. 100 fb-1 LHeC: 10 fb-1 per charge = 0.1 e- _ q or q ? 12/Jan/2008 7 Inclusive Kinematics for 70 GeV x 7 TeV New physics, distance scales few . 10-20 m Large x partons High precision partons in LHC plateau High Density Matter 12/Jan/2008 Low x parton dynamics s 1.4 TeV W 1.4 TeV 7 x 10 at Q2 1 GeV2 • High mass (Q2) frontier • Q2 lever-arm at moderate x • Low x (high W) frontier 8 Event Rates: Ee x 7000 GeV Neutral Currents electrons positrons Charged Currents 100 fb-1 70 GeV 10 fb-1 140 GeV 12/Jan/2008 2 times Ee compensates for 10 times the energy at highest Q2 9 High x Partons と as Full NC/CC sim (with systs) & NLO DGLAP fit … … high x pdfs LHC discovery & interpretation of new states? … projected as precision few/mil (c.f. 1-2% now) 12/Jan/2008 10 Heavy Quarks bottom High precision c, b measurements (modern Si trackers, beam spot 15 * 35 m2 , increased rates at larger scales). Systematics at 10% level beauty is a low x observable! s (& sbar) from charged current LHeC 10o acceptance strange LHeC 1o acceptance (A. Mehta, M. Klein) (Assumes 1 fb-1 and - 50% beauty, 10% charm efficiency - 1% uds c mistag probability. - 10% c b mistag) 12/Jan/2008 11 Impact of CTEQ6.5M,S,C PDF’s on stot’s at LHC 12 W, Z production : really standard candles? + Wu-Ki Tung @ DIS2007 Useful general results: LHC Luminosities Yuan: EW Cteq6.5 err. band CTEQ 6.1 -> 6.5: Difference in HQ treatment： Cteq6.1 err. band MZ MW D ~7%, (outside error band) 12/Jan/2008 Through the global fitting of PDF, → change in Gluon → change in Sea quark Change in W-production @ LHC LHC data help to improve PDF. 12 SUSYのパラメータ領域では、 陽子の中のb-クォーク分布が大きく効く場合もある。 ―> SUSYパラメータの決定の上でも、重要になってくる可能性がある。 Higgs <-SM MSSM-> 12/Jan/2008 13 Low x MachineとしてのLHeC HERAからさらにlow-x へ拡張できる。 INCREDIBLE LOW x COVERAGE! ただし実験的には 非常に難しい。 電子のエネルギーが 高いために、LowQ2では 散乱角が非常に小さい。 179度 ―> Q2＝1GeV2 ただしルミノシティーは たいしていらない。 Saturationに答えを出せる （か？） 12/Jan/2008 14 HERA の場合 Gluck, Reya and Vogt “pQCD” : parton evolution 1 0 Fixed target data Early ZEUS data showed rapid increase of F2 at low x. “Hadronic”: Regge theory 12/Jan/2008 behavior of γp total cross section15 Donnachie & Landshoff F2 構造関数の測定 • xが小さくなるとF2 は急激に大きくなる – 陽子の中にはsoft ‘sea’ クォークがたくさん ある • Q2 が大きくなるにつれてその傾きは急 になっている。 softer parton resol. smaller dynamics of quarks and gluons • 高いxでは低エネルギーのデータとよく つながっている。 • DGLAP発展方程式を使ったNLOQCD はデータを非常に良く再現できている。 12/Jan/2008 16 12/Jan/2008 17 LHeC の場合 : どのSaturation模型か？ Forshaw, Sandapen, Shaw hep-ph/0411337,0608161 FS04 Regge (~FKS): 2 pomeron model, no saturation FS04 Satn: Simple implementation of saturation CGC: Colour Glass Condensate version of saturation 12/Jan/2008 18 Saturation model 毎の 違いを議論できるか？ ―>もっとStudyが必要 !! eAも可能 !! J. Forshow, P. Newmann 12/Jan/2008 19 どうやって LHeC を実現するか ep と pp が同時に実験できるオプション以外はない。 電子加速器を建設する機会はLHCアップグレードのときのみ LINAC-RING RING-RING • Previously considered as `QCD explorer’ (also THERA) • First considered (as LEPxLHC) in 1984 ECFA workshop • Reconsideration (Chattopadhyay & Zimmermann) with CW cavities began • Recent detailed re-evaluation with new e ring (Willeke) • Main advantages: low interference with LHC, Ee 140 GeV, LC relation • Main advantage: high peak lumi obtainable (1033 cm-2 s-1) • Main difficulty: peak luminosity only 32 cm-2 s-1 at reasonable power ~0.5.10 12/Jan/2008 • Main difficulties: building it around existing LHC, e beam life 20 Ring-Ring Parameters • LHC fixes p beam parameters Top view • 70 GeV electron beam, (compromise energy v synchrotron 50 MW) • Match e & p beam shapes, sizes Non-colliding p beam Vertically displaced • Fast separation of beams with tolerable synchrotron power requires finite crossing angle • 2 mrad angle gives 8s separation at first parasitic crossing 2 mrad • High luminosity running requires low b focusing quadrupoles close to interaction point (1.2 m) acceptance limitation to 10o of beampipe 12/Jan/2008 21 Ring-Ring Design • e ring would have to bypass experiments and P3 and 6 • ep/eA interaction region could be in P2 or P8. 12/Jan/2008 22 Linac-Ring Design (70 GeV electron beam at 23 MV/m is 3km + gaps) 6km alternative sites S. Chattopadhyay (Cockcroft), F.Zimmermann (CERN), et al. Relatively low peak lumi, but good average lumi Energy recovery in CW mode (else prohibitive power usage) 12/Jan/2008 23 Comparison Linac-Ring and Ring-Ring Energy / GeV 40-140 Luminosity / 1032 cm-2 s-1 0.5 Mean Luminosity, relative 2 Lepton Polarisation Tunnel / km Biggest challenge Biggest limitation IR Plenary ECFA, LHeC, Max Klein, CERN 30.11.2007 60-80% 6 CW cavities luminosity (ERL,CW) not considered yet one design? (eRHIC) 40-80 10 1 [dump at L peak /e] 30% [?] 2.5=0.5 * 5 bypasses Civil Engineering Ring+Rf installation maximum energy allows ep+pp 2 configurations [lox, hiq] e±p Luminosity Ring-ring Linac-ring Timeline ● 2007: form working groups + steering committee initial meeting of conveners + committee SAC overview ● 2007/8: ECFA/CERN endorsement “work out” ● 2008: workshop I ● 2009: workshop II LHeC CDR [LHC Committee] ● 2011: LHeC TDR - construction 8 years ? - impact on LHC: civil engineering + installation e-ring and e-linac - be aware of CLIC progress 12/Jan/2008 26 Scientific Advisory Committee (SAC) Accelerator Experts S.Chattopadhyay, R.Garoby, S.Myers, A. Skrinsky, F.Willeke Research Directors J.Engelen (CERN), R.Heuer (DESY), Y-K.Kim (Fermilab), P.Bond (BNL) Theorists G.Altarelli, S.Brodsky, J.Ellis, L.Lipatov, F. Wilczek Experimentalists A.Caldwell (chair), J.Dainton, J.Feltesse, R.Horisberger, A.Levy, R.Milner 12/Jan/2008 27 Steering Group Oliver Bruening (CERN) John Dainton (Cockcroft) Albert DeRoeck (CERN) Stefano Forte (Milano) Max Klein - chair (Liverpool) Paul Newman (Birmingham) Emmanuelle Perez (CERN) Wesley Smith (Wisconsin) Bernd Surrow (MIT) Katsuo Tokushuku (KEK) Urs Wiedemann (CERN) + (increasing) 12/Jan/2008 28 Working Group Structure •Accelerator Design [RR and LR] •Interaction Region and Forward Detectors •Infrastructure •Detector Design •New Physics at Large Scales •Precision QCD and Electroweak Interactions •Physics at High Parton Densities [small x and eA] Convenors 候補者にコンタクトを 取っているところ ―> ぜひ参加を 12/Jan/2008 29 pn 3.8m Luminosity: Ring-Ring N p 1.71011 N p Ie I m L 8.31032 e cm2s1 4epn b pxb py 50mA b pxb pn s p(x,y) s e(x,y) b px 1.8m b py 0.5m 4 P 100GeV Ie 0.35mA MW E e Ie = 100 mA 1033 likely klystron installation limit Synchrotron rad! 1033 can be reached in RR Ee = 40-80 GeV & P = 5-60 MW. HERA was 1-4 1031 cm-2 s-1 huge gain with SLHC p beam F.Willeke in hep-ex/0603016: Design of interaction region for 1033 : 50 MW, 70 GeV May reach 1034 with ERL in bypasses, or/and reduce power. R&D performed at BNL/eRHIC Plenary ECFA, LHeC, Max Klein, CERN 30.11.2007 cf also A.Verdier 1990, E.Keil 1986 Luminosity: Linac-Ring pn 3.8m P N p 32 P / MW 2 1 L 110 cm s 4epnb* Ee Ee /GeV N p 1.71011 b * 0.15m Ie 100mA Ie = 100 mA LHeC as Linac-Ring version can be as luminous as HERA II: High cryo load to CW cavities s 2TeV Plenary ECFA, LHeC, Max Klein, CERN 30.11.2007 P GeV MW Ee 4 1031 can be reached with LR: Ee = 40-140 GeV & P=20-60 MW LR: average lumi close to peak 140 GeV at 23 MV/m is 6km +gaps Luminosity horizon: high power: ERL (2 Linacs?)