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LHeC に向けて

antiprotons. protons. LHeC に向けて. protons. electrons?. protons. ＫＥＫ　徳宿克夫 2008 年 1 月 12 日. nuclei. proton. HERA: (27.5 GeV e vs 920GeV p) LHeC (70GeV e vs 7000GeV p). LHeC. 歴史. “ Deep Inelastic Electron-Nucleon Scattering at the LHC ”

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LHeC に向けて

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  1. antiprotons protons LHeC に向けて protons electrons? protons ＫＥＫ　徳宿克夫 2008年1月12日

  2. nuclei proton HERA: (27.5 GeVevs920GeVp) LHeC (70GeV e vs 7000GeV p) LHeC

  3. 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

  4. Inclusive Kinematics for 70 GeV x 7 TeV New physics, distance scales few . 10-20 m Large x partons • High mass • (Q2) frontier • Q2 lever-arm • at moderate x • Low x (high W) • frontier High precision partons in LHC plateau Low x parton dynamics High Density Matter

  5. ●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？ LHeC　　もともとある 　　クォークとレプトンから作れる LHC　対生成 Re + resonance LHCで発見された後、LHeCで狙いを定めて精密測定

  6. 対生成の断面積は、QCD：　αs　とマスで決まる。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。

  7. + F = -1 _ F = +1 e, _ q or q ? q e+ q or q ? e- 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 LHC: single prod. 100 fb-1 LHeC: 10 fb-1 per charge Asymmetry  = 0.1

  8. 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 mass • (Q2) frontier • Q2 lever-arm • at moderate x • Low x (high W) • frontier Low x parton dynamics High Density Matter

  9. Neutral Currents Charged Currents electrons positrons 100 fb-1 70 GeV Event Rates: Ee x 7000 GeV 10 fb-1 140 GeV 2 times Ee compensates for 10 times the energy at highest Q2

  10. High x Partons とas Full NC/CC sim (with systs) & NLO DGLAP fit … … high x pdfs  LHC discovery & interpretation of new states? … projectedas precision few/mil (c.f. 1-2% now)

  11. 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 Heavy Quarks LHeC 10o acceptance LHeC 1o acceptance strange (A. Mehta, M. Klein) • (Assumes 1 fb-1 and • 50% beauty, 10% • charm efficiency • 1% uds  c • mistag probability. • 10% c  b mistag)

  12. 12 W, Z production : really standard candles? Wu-Ki Tung @ DIS2007 CTEQ 6.1 -> 6.5: Difference in HQ treatment： Through the global fitting of PDF, 　　　→　change in Gluon →　change in Sea quark Change in W-production @ LHC LHC data help to improve PDF.

  13. 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->

  14. Low x MachineとしてのLHeC INCREDIBLE LOW x COVERAGE! HERAからさらにlow-x へ拡張できる。 　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？）

  15. HERA の場合 Gluck, Reya and Vogt “pQCD” : parton evolution HERA Kinematic Limit 1 Fixed target data 0 Early ZEUS data showed rapid increase of F2 at low x. “Hadronic”: Regge theory behavior of γp total cross section Donnachie & Landshoff

  16. 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 smaller resol. 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。

  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

  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

  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) • Reconsideration (Chattopadhyay • & Zimmermann) with CW cavities began • Main advantages: low interference • with LHC, Ee  140 GeV, LC relation • Main difficulty: peak luminosity only • ~0.5.1032 cm-2 s-1 at reasonable power • First considered (as LEPxLHC) • in 1984 ECFA workshop • Recent detailed re-evaluation • with new e ring (Willeke) • Main advantage: high peak • lumi obtainable (1033 cm-2 s-1) • Main difficulties: building it • around existing LHC, e beam life

  20. Ring-RingParameters • LHC fixes p beam parameters • 70 GeV electron beam, (compromise • energy v synchrotron  50 MW) • Match e & p beam shapes, sizes • Fast separation of beams with • tolerable synchrotron power • requires finite crossing angle • 2 mrad angle gives 8s separation at • first parasitic crossing • High luminosity running requires low b • focusing quadrupoles close to interaction • point (1.2 m)  acceptance limitation to 10o of beampipe Top view Non-colliding p beam Vertically displaced 2 mrad

  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.

  22. (70 GeV electron beam at 23 MV/m is 3km + gaps) Linac-Ring Design 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)

  23. Energy / GeV 40-140 40-80 Luminosity / 1032 cm-2 s-1 0.5 10 Mean Luminosity, relative 2 1 [dump at Lpeak /e] Lepton Polarisation 60-80% 30% [?] Tunnel / km 6 2.5=0.5 * 5 bypasses Biggest challenge CW cavities Civil Engineering Ring+Rf installation Biggest limitation luminosity (ERL,CW) maximum energy IR not considered yet allows ep+pp one design? (eRHIC) 2 configurations [lox, hiq] Comparison Linac-Ring and Ring-Ring

  24. e±p Luminosity Ring-ring Linac-ring

  25. ●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 Timeline

  26. 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 Scientific Advisory Committee (SAC)

  27. 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) Steering Group

  28. 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] Working Group Structure Convenors 候補者にコンタクトを 取っているところ ―>　ぜひ参加を

  29. Luminosity: Ring-Ring 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  Ie = 100 mA likely klystron installation limit Synchrotron rad! 1033 cf also A.Verdier 1990, E.Keil 1986

  30. Luminosity: Linac-Ring  Ie = 100 mA LHeC as Linac-Ring version can be as luminous as HERA II: 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?) High cryo load to CW cavities

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