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NA48

NA48. INFN-CSN1 Frascati E. Iacopini 11 Novembre 2003. SPSC del 28 ottobre…. Status Report di NA48/1: Augusto Ceccucci (run Ks ad alta intensità del 2000 e 2002) Status Report di NA48/2: Vladimir Kekelidze (run K carichi 2003). from NA48/1. K S → p 0 ee.

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NA48

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  1. NA48 INFN-CSN1 Frascati E. Iacopini 11 Novembre 2003

  2. SPSC del 28 ottobre… Status Report di NA48/1:Augusto Ceccucci (run Ks ad alta intensità del 2000 e 2002) Status Report di NA48/2:Vladimir Kekelidze (run K carichi 2003)

  3. from NA48/1

  4. KS→p0 ee • 7 candidates • in the signal region • 0 in the control region • Background: 0.15 events • The probability that all 7 • events are background • is ~10-10 meegg (GeV/c2) mgg (GeV/c2) First observation of KS→p0 ee October 28, 2003 A. Ceccucci: NA48/1 Status Report to SPSC

  5. …dalla mia presentazione di Lecce … KS→p0mm Presto il risultato ! … Mmmgg Mgg

  6. Six candidates!! The red dots are the events passing 0 < tK < 3 tS KL→p0p+p- m m m October 28, 2003 A. Ceccucci: NA48/1 Status Report to SPSC

  7. The six KS→p0mmcandidates • Consistent with being a signal • BR measurement in progress … October 28, 2003 A. Ceccucci: NA48/1 Status Report to SPSC

  8. KS , 0ee fattore di forma (O(p6)): (Buchalla, D’Ambrosio,Isidori:hep-ph/0308008) (piccolo, determinato dall’ampiezza K→ 3p) KS p0e+e-

  9. First Observation • The b decay of X0 is the only source of S + in the neutral beam … The plot shows the pp0 invariant mass, for decays with one identified muon October 28, 2003 A. Ceccucci: NA48/1 Status Report to SPSC

  10. from NA48/2

  11. I Fasci … Sezione verticale:gli assi dei fasci vengono fatti coincidere entro ~ 1 mm

  12. NA48 Set-Up

  13. New K12 beam line built for NA48/2 second achromat first achromat

  14. …dalla mia presentazione di Lecce … La Fisica … • Misura della violazione diretta di CP nei decadimenti dei K+ e K– in tre pioni carichi: M(u,v)21 + gu + hu2 + kv2 u = (2M/m2) (M/3 - E*) CP  Ag (g+  g–)/(g++ g–)  0 Una “slope” inR (u) N+(u) / N–(u) aAg0 ... e la sensibilità prevista nella proposta era :Ag= 1.7  10-4 • Misura del “quark condensate” <q q> della cPT attraverso la reazione Ke4 , i.e. K  e+ -n (n) _ _

  15. Dalitz plot

  16. …dalla mia presentazione di Lecce … Strategia della misura

  17. Statistics for asymmetry Statistics ofsupersamplesin mln K±  ±+ - 1 2 3 total HDBU HDBD HUBU HUBD 98 166 38 302 150 58 86 294 127 162 50 339 130 142 60 332 total 505 528 234 1313 ~ 450mlnK±  ± + -events of SS-1 reprocessed for the express analysis October 28, 2003 V. Kekelidze: NA48/2 Status Report to SPSC

  18. aJ aS(u) aJ(u) accettanza aS aJ(u) aS(u) Osservabili aS&aJ :slopes di R(u)=N+(u)/N-(u)  r (1+a u) t ~ 1 giorno BUN+(u) BDN+(u) BUN-(u) BDN-(u) aS =Dg=aJ seaS(u)& aJ(u) rimangono stabili a 0.5(aS +aJ) = g seaS(u),aJ(u) cambiano simmetricamente

  19. Checks Sistematici di accettanza Ra(u) =aS(u)/aJ(u)(1+da)u a+ BUN+(u) BDN+(u) aJ(u) aS(u) aD  t = 1 day  aU  a- BUN-(u) BDN-(u) aJ(u) aS(u) a+  da; a-  -da; (a++a-)/2  0 aU  g+da; aD  g-da (aU+aD)/2  g … sedaè stabile nel tempo …

  20. Acceptance cancellation check < a±> = (a++a-)/2 = (1.2  2.3)10-4 a+ a- (a+ + a-)/2 October 28, 2003 V. Kekelidze: NA48/2 Status Report to SPSC

  21. Dg stability with momentum (aS + aJ)/2 + offset October 28, 2003 V. Kekelidze: NA48/2 Status Report to SPSC

  22. Time stability of acceptances aS + offset aJ + offset different achromats different achromats HD HU HD HU October 28, 2003 V. Kekelidze: NA48/2 Status Report to SPSC

  23. Time stability of Dg (aS + aJ)/2 + offset HD HU October 28, 2003 V. Kekelidze: NA48/2 Status Report to SPSC

  24. Systematics summary • Major systematics related to - acceptance asymmetry - time variation effects are under control • Other possible systematics: • - residual (+ Earth) magnetic fields • - trigger efficiencies • - DCH’s efficiencies • - accidentals • - ….. • are found much less significant October 28, 2003 V. Kekelidze: NA48/2 Status Report to SPSC

  25. October 28, 2003 V. Kekelidze: NA48/2 Status Report to SPSC Beam Request for 2004 • as much proton time as possible • (400 GeV protons ~1·1012 ppp on T10) • as few beam interruptions as necessary Conclusion • NA48/2 experiment has been prepared: • beam line, detector and trigger • are put in operation & tuned • the major systematics are under control • & do not exceed statistical precision • toreach the proposal goals • morestatisticsare needed

  26. Conclusione finale • Al momento non sono ancora disponibili le minute • dell’SPSC … ; • informalmente sembra che il Comitato raccomanderà • al RB che NA48 possa prendere dati anche nel 2004, • per  3 mesi … • … il prossimo RB sarà il 13 novembre

  27. Spares

  28. KABES-1/2 (moved out by ~20 cm) Beam rate ~20 MHz K+ time resolution 67 ps entrance window K+, K- X,Y space resolution ~100 mm T/2 ns, Station2 – Station3 K- time resolution 63 ps -10 0 10 T/2 ns, Station2 – Station3 Beam rate ~20 MHz Momentum resolution 1.1% P(K), GeV/c 50 60 70 -0.2 0 +0.2 50 60 70 P0/P(K) - P0/P(S) P(S) , GeV/c

  29. Foto

  30. K+ K+ K- P, GeV/c 0 K- 0 40 50 60 70 80 M(3)+GeV/c2 M(3)-GeV/c2 PK, GeV/c Reconstructed K±  ± + -

  31. Selection criteria • radial cuts around the beam centres (in DCH1,4) to symmetrize acceptances • day-by-day definition of the beam COG’s in each momentum bin to reduce acceptance variations in time Conservative cuts: R(DCH1)> 11.5 cm R(DCH4)> 13.5 cm lead to 40% statistics lost (beam stability dependent)

  32. Spectrometer alignment (after fine tuning of B) surprising effect MK – MPDG, KeV/c2 BUK+ & BDK- (to Jura) ~4 m / day x DCH4 ~ 35 KeV/c2 time variation termwas compensated BDK+ &BUK- (toSaleve) day-sample

  33. R(u)J aS(u) aJ(u) accettanza R(u)S aJ(u) aS(u) Osservabili AS&AJ - slopes di R(u)=N+(u)/N-(u) t ~ 1 giorno BUN+(u) BDN+(u) BUN-(u) BDN-(u) R(u)S =R(u)J  1+Dg seaS(u)& aJ(u) sono stabili nel tempo R=0.5(RS +RJ)  1+g seRa(u) =aS(u)/aJ(u) è stabile nel tempo

  34. Checks Sistematici +Sa BUN+(u) R+ BDN+(u) RD  t = 1 day  RU  -Sa +Sa -Sa R- BUN-(u) BDN-(u) Ra(u) =aS(u)/aJ(u): Sa - slope RU  1+g+Sa; RD  1+g-Sa (RU+ RD)/2  1+g seSaè stabile nel tempo R+  1+Sa; R-  1-Sa; (R++ R-)/2  0

  35. > 0 < 0 Beam geometry effects a± for different achromat polarities (a+ + a-)/2 (a+ + a-)/2 BD BU October 28, 2003 V. Kekelidze: NA48/2 Status Report to SPSC

  36. First look on K±  + - e± n PDG K±mass 15807 events inSS-1 BR =(3.87 ± 0.20)10-5 (PDG:(4.08 ± 0.09)10-5) Background ~1% of Ke4 fromK±  +- p± ~1% of Ke4 fromK±  p± 0D M(3)GeV/c2 7105expected K±  + - e±n in 2003 PK, GeV/c

  37. Time stability of acceptancesin momentum bins aS + offset aJ + offset October 28, 2003 V. Kekelidze: NA48/2 Status Report to SPSC

  38. Rare decayK  p  e+ e- : BR2.9 10-7 1400events in 1 month of data taking ~ 3500events expected in 2003 run Events / 2 MeV/c2 500 400 300 200 100 0 M(pe+ e -), GeV/c2 October 28, 2003 V. Kekelidze: NA48/2 Status Report

  39. …dalla mia presentazione di Lecce … la statistica effettiva…

  40. SS-1 August 6- 20 Beam availability & supersamples

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