1. LBOC31-May-2011 CERNMassimiliano Ferro-Luzzi 1 The usual "wishes from the experiments"  Going to stable beams / optimizing / leveling  Filling the LHC... Can Not Go Swifter ?  Special requests for the near future: –ALICE reversal –Roman Pots completion (90m being discussed) –less work intensive: LHCb reversal, ALICE fields off

2. LBOC31-May-2011 CERNMassimiliano Ferro-Luzzi 2 Comment on IP2 & IP8 lumi limits ALICE (IP2) 10m  Peak lumi over 1e31 Hz/cm 2 can cause detector HV trips –has been a worry with 75ns spacing and many bunches –potentially damaging some electronics, but mostly data loss –see A. Di Mauro in MPP 2011-42, 25 Mar 2011, herehere  With current  *,  T, N: max lumi ~ n 2  2e29 Hz/cm 2 (if put head-on)  With 50ns schemes, generally n 2 < 50 thus L 2 < 1e31 Hz/cm 2 –Looks like it's SAFE, even if put head-on LHCb (IP8) 3m  Too high peak lumi not considered a protection issue, but a serious performance issue (loss of data...). Thus, aim at following: L 8 < ~1.5e32 start of fill, then slowly move up to ~3...4e32 Hz/cm 2  With current  *,  T, N: max lumi ~ n 8  7e29 Hz/cm 2 (if put head-on)  With 50ns, could reach n 8 ~1300 thus L 8 ~ 9e32 Hz/cm 2 n 2 = nr of IP2 colliding pairs

3. LBOC31-May-2011 CERNMassimiliano Ferro-Luzzi 3 LHCb Luminosity Leveling Courtesy: Richard Jacobsson  Direct tool to maximize LHCb physics yield  Thanks! It really works very well!  Reminder: LHCb design specs: 2x10 32 cm -2 s -1 with 2622 bunches (  ~0.4) –Current achievement:  max  ~ 2.5, luminosity 3x10 32 cm -2 s -1 –Aim: >3 x 10 32 cm -2 s -1 with >1300 bunches Comment from LPC: We should help them! This will make it easier to deliver the 1fb -1 in 2011 (which is a real challenge) Requires => leveling procedure => as many bunches as possible ! Comment from LPC: We should help them! This will make it easier to deliver the 1fb -1 in 2011 (which is a real challenge) Requires => leveling procedure => as many bunches as possible !

4. LBOC31-May-2011 CERNMassimiliano Ferro-Luzzi 4 Exclusion limit @ 90% C.L. reminder... B s →μ + μ - search at LHCb 2010 LHCb results are out 2011 data will approach SM Sensitive to new physics, FCNC, e.g. SUSY Higgs M A =600, tanβ~30 excludable To match this limit, would need hundreds of fb -1 in a direct search Strongly suppressed in Standard Model!! Possible enhancement by New Physics!! Give LHCb >1 fb -1 and they'll either discover SUSY or rule out large chunks of parameter space Physics Letters B 699 (2011) 330

5. LBOC31-May-2011 CERNMassimiliano Ferro-Luzzi 5 LHCb Luminosity Leveling Courtesy: Richard Jacobsson  Direct tool to maximize LHCb physics yield  Thanks! It really works very well!  Reminder: LHCb design specs: 2x10 32 cm -2 s -1 with 2622 bunches (  ~0.4) –Current achievement:  max  ~ 2.5, luminosity 3x10 32 cm -2 s -1 –Aim: >3 x 10 32 cm -2 s -1 with >1300 bunches  Optimum luminosity is a function of several parameters monitored real-time –Full event readout rate (max 1 MHz) –Average number of interactions per crossing (max 2.5) –Max readout network through-put (max 70 GB/s) –Physics trigger overall dead-time ( <5%) –High Level Trigger output rate to storage (max ~4-5 kHz) –Instantaneous luminosity ( max ?  = Detector/operational stability, still exploring) –Behaviour and limits of parameters depend on experimental conditions (background/beam- gas/…) and system status  Target luminosity determined real-time with slow time constants  At extreme conditions, problem is not high luminosity but fast onset of high luminosity  Detector HV trips/conditioning  Bandwidth shockwave

6. LBOC31-May-2011 CERNMassimiliano Ferro-Luzzi 6 LHCb Leveling Procedure (wish) Courtesy: Richard Jacobsson  ADJUST 1.LHC Lumi Leveling OFF, LHCb Lumi Leveling OFF 2.Collapse separation bump to constant offset (e.g. ~2-3  )  L ~ 1.5x10 32 cm -2 s -1 in vertical  Separation will have to be bigger at >1300 bunches  STABLE BEAMS 1.Optimize in horizontal (crossing plane) keeping vertical constant 2.Switch ON LHC Lumi Leveling 3.VELO closing with initial luminosity 4.LHCb Lumi Leveling switch ON, Target Luminosity updated and leveling requested 5.Luminosity increase to target in few minutes  Coast –Lumi Leveling requested when current luminosity and target different by > 3%  LHC Lumi Leveling trigger threshold is 5%  Alternative: Horizontal optimization could be done in Stable Beams but prefer to avoid in parallel to VELO closure procedure (sensitive to 10  m)  Actions –Tune LHC Lumi Leveling parameters (step size and luminosity integration time) –Reduce EIC “confirmations” (one per target change)

7. LBOC31-May-2011 CERNMassimiliano Ferro-Luzzi 7 Going to stable beams: proposal  Collapse bumps –make sure LHCb / ALICE arrive at sufficiently large separation (V / H)  the non-leveling plane should collapse to maximum  the leveling plane should collapse to separation of ~3 / 4  beam (IP8 / IP2) (i.e. separation ~130 / 320 µm for IP8 / IP2)  LHCb: L 8 ~ 0.1... 1e32 Hz/cm 2  ALICE: L 2 ~ 0.1... 1e30 Hz/cm 2  Declare STABLE BEAMS  "Optimize All": IP1/5 H+V, IP8 H, IP2 V –generally, use the experiments' luminometers. If not available, keep going with BRANs and phone calls...  Start leveling IP8 V (automated), IP2 H (not yet automated) –LHCb manages internally its VELO closing

8. LBOC31-May-2011 CERNMassimiliano Ferro-Luzzi 8 Filling the LHC: Can Not Get Swifter ?  This is typical (but here accelerated for you): Wooops, rephasing needed...

9. LBOC31-May-2011 CERNMassimiliano Ferro-Luzzi 9 A recent and quite fast (50ns) filling I have found 50ns_1092b+1small_1042_35_1008_108bpi13inj still 42s 19min  It can go fast  It could go even faster LHC BCTDCs TI2/TI8 BCTs

10. LBOC31-May-2011 CERNMassimiliano Ferro-Luzzi 10 Can it be tried ?  Can the LHC take one injection per ring (alternated) at a pace of 1 injection per 18 seconds ? A) normally done: 4 CNGS cycles + 1 LHC, which gives ~42 lo o o oo o o ong seconds per LHC injection B) could one do: LHC and nothing else => 18 seconds per injection ?  No impact on CNGS! (pot cost-neutral) –Perhaps more impact on some NH expts  For example 1380b: 2 probes + 2x12b + 22 x50ns injections In best case: –case A: 15.4 min to fill, of which 8.8 min of FT cycles –case B: 6.6 min to fill, followed by 8.8 min pure FT

11. LBOC31-May-2011 CERNMassimiliano Ferro-Luzzi 11 "But what about fixed target physics ?"  The bottom line is: for what concerns the Physics Coordinator s, you don't have to sit and wait for the next X fixed target cycles before an LHC injection.

12. LBOC31-May-2011 CERNMassimiliano Ferro-Luzzi 12 Why care ? It's only 9 minutes...  9 minutes of beam time ( = machine available time!) per refill –this is highly precious time  Say we expect 200 more fill attempts this year => ~30 hours of beam time could be saved  That's about as much as we plan to invest in special physics requests (90m physics, special lumi calibration fills) for the whole year

13. LBOC31-May-2011 CERNMassimiliano Ferro-Luzzi 13 Squeeze as much as reasonably possible

14. LBOC31-May-2011 CERNMassimiliano Ferro-Luzzi 14 near future special requests...  towards a long, quiet and productive summer

15. LBOC31-May-2011 CERNMassimiliano Ferro-Luzzi 15 The dream  Reach stable configuration with 1380b before the next MD session  Still to do before that: –ALICE polarity reversal: TDI realign, TCTs IR2, loss maps => 2 shifts ?  Just after the Ascension week-end,... Monday-Tuesday next week ?  Will allow ALICE to take sufficient data with the reversed polarity before the TS (and summer conferences)  No more ALICE reversals before ion run –Roman Pots: second session, finish the TOTEM (147m) pots ~8h  This time try it in one fill... (including all loss maps)  Some time before the next MD (end of June) –LHCb polarity reversal  quite transparent (if experts present)  around mid June –One fill with ALICE fields off (if no change of collimators needed)  some time soon after the reversal  From July TS to September TS: special activities for experiments are being strongly discouraged! check that net angle still OK

16. LBOC31-May-2011 CERNMassimiliano Ferro-Luzzi 16 Little reminder 1 fb -1 2 fb -1 5 fb -1 1 fb -1 seems well possible for the summer conferences !! FANTASTIC

17. LBOC31-May-2011 CERNMassimiliano Ferro-Luzzi 17 New physics ? CDF, 4.3 fb -1

18. LBOC31-May-2011 CERNMassimiliano Ferro-Luzzi 18Whoops…!  Some trips…

19. LBOC31-May-2011 CERNMassimiliano Ferro-Luzzi 19 Leveling example 1. Avoid head-on at collapse of separation bump  rather “any luminosity” O(1x10 32 ) 2. First estimate of target luminosity immediately when VELO reaches closed position 3. Possible update of target luminosity when reached but rare –Further updates of target luminosity during the fill possible (if >3%), but rare STABLE BEAMS