Results of the LHCf experiment so far and future prospects

Transcription

1 Results of the LHCf exeriment so far and future rosects K.Kasahara for the LHCf collaboration. Waseda Univ. Jun for s=1 ev@lhcf hut Collaborators are always squeezable in a recognizable hoto! MPI worksho Nov. 27, rieste,italy 1

2 Physics motivation of the LHCf exeriment o have better understanding of very high energy cosmic-rays Good hadronic interaction model(s) for M.C LHCf affords stuff for selecting good models or for tuning the models. 2

3 E LHC Auger (201) A (2015) rm M.Nagano: New Journal of Physics 11 (2009)

4 Why sectrum shae changes? Is it related to the comosition change? Accel. mechanism, source? E Comosition vs Energy is key LHC Auger (201) A (2015) rm M.Nagano: New Journal of Physics 11 (2009)

5 Air shower observation Fluorescence Xmax SD 4 few ~ km FD

6 Xmax: F(E0, 1ry tye, interaction model) Several interaction models in the cosmic ray field qgsjetii EPOS sibyll dmjet ythia (H.E field) Pre-LHC, no reliable info. about what is haening at > 15 ev. But we have been using them even at 20 ev! 5

7 η-distribution:in terms of number and energy in CMS 6

8 Meta%analysis:,Comosi1on,WG, [618,%,PoS,07,, Parallel#CR07#EAS#mass## rack:#crex,#presented#by# Michael#UNGER# on#1#jul#2015#at#14:00## Unger#et#al,#PoS#07# A ICRC 2015 Fe A#data#cannot# dis,nguish# between#mix#and# QGSJEII;0# rotons#at#this# level#of#systema,c# uncertainty.# From talk by Fukushima 7

9 LHCf is dedicated to measure hotons, i0 s and neutrons near zero degree. 8

10 AN area neutral articles Samling calorimeter W of 44 X0, 1.7λc Plastic scinti. GSO lates 4 os. sensitive layers: Arm1: SciFi GSO bars Arm2: Si stri From 2014 front counter Large tower 2 tower calorimeters Small tower 96mm 9

11 Summary of the LHCf exeriment Year Beam SNN Detectors Equiv. roton lab. E (ev) γ Neutron π ,,12, 14 SPS beam test Arm1,2 NIM A, 871, 129 (2012) JINS 9 P0016 (2014) GeV Arm1,2 4.x 14 PLB 715, 298(2012) 2009/ ev Arm1, ev Arm2 Pb 5.02 ev Arm2 1 ev Arm1,2 SPS beam test Arm1,2 2.6x 16 PLB 70, 128 (2011) PLB 750(2015) PRD 86, (2012) 4.1x 15 PRC 89, First trial of common RG (2014) 1.x 16 with ALAS. Some reliminary results 9.0x 16 Our main target. Data taken in June 2015 after the LHC restart! Post LHC calibration Combined analysis aer: submitted to PRD Quick Reort

12 Results hoton S= 7 ev Comarison with M.C redictions Small ower; eta >.94 Large ower; 8.81<eta<8.99

13 hoton S= 7 ev Comarison with M.C redictions Small ower; eta >.94 MC/Data dmjet ythia qgsjetii-0 eos1.99 sibyll2.1 Large ower; 8.81<eta<8.99 No model is erfect but not too bad LHC-tuned EPOS and QGSJEII show bit harder sectra and MC/Data will be imroved a bit 12

14 hoton S= 7 ev Comarison with M.C redictions Small ower; eta >.94 MC/Data dmjet ythia qgsjetii-0 eos1.99 sibyll2.1 Large ower; 8.81<eta<8.99 No model is erfect but not too bad LHC-tuned EPOS and QGSJEII show bit harder sectra and MC/Data will be imroved a bit 12

15 π 0 analysis Pz sectrum at s = 7 ev (Arm1,2 combined) [GeV σ/d Ed (a)(b) < < [GeV [GeV < 0.2 < 0.4 LHCf QGSJEII-04 Sibyll2.1 EPOS-LHC [GeV 1 Pz (GeV) (GeV) (d) 0.6 < s=7ev Ldt= nb -1 [GeV σ/d Ed [GeV < (b) 0.2 < (e) 0.8 [G <

16 1/σ in 5 E Pz sectrum of π 0 (Arm1,2 combined) at S = 7 ev 1/σ in E E 1/σ in 11 ev [GeV (i).4 < [GeV 0.2< y < nb [GeV [GeV σ/d σ/d Ed Ed -1 inel LHCf [GeV 1 (a) (d) (b) [GeV < < [GeV (j) [GeV < y <.8 s=7ev Ldt= nb -1 [GeV < 0.8 (e) 0.8 < [GeV < 1.0 GeV line). Exerimental combined [GeV [GeV z sectra of the LHCf detector (filled [GeV circles) in + collision z s indicate the total statistical and systematic uncertainties. he redictions of hadronic in In these Pt regions, Sibyll2.1 deviates from the data. arison LHCf (stat.+syst.) How (seeabout textpt for dist.? details.) FIG. 5: (color online). Exerimental combined z sectra of the LHCf detector (filled circles) in Shaded rectangles indicate the total statistical and systematicdpmje uncertainties..06 he redictions are shown for comarison (see text for details.) QGSJE II-04 n + Pb collisions at s NN =5.02 ev only the LHCf Arm2 detector was oer SIBYLL [GeV σ/d Ed σ inel 1 [GeV σ/d Ed z [GeV σ/d Ed inel [GeV (a) 8.8 < y < (c) (e) < [GeV z [GeV LHCf (stat.+syst.) DPMJE.06 QGSJE II-04 SIBYLL 2.1 PYHIA EPOS LHC [GeV < (b) 9.0 < y < 9.2 PYHIA 8.185(c) 9.2 < y < 9.4 [GeV collisions at s NN =5.02 ev. Figure 8 shows the LHCf sectra

17 E [GeV σ/d Ed i).4 [GeV < y < LHCf 0.5 [GeV 1 σ/d Ed [GeV σ/d Ed (a) (i) [GeV < y < s=7ev Ldt= nb [GeV -1 E (j).6 [GeV < y <.8 [GeV σ/d Ed [GeV 1/σ Ed σ/d inel Pt sectrum of π 0 (Arm1,2 combined) at S = 7 ev (j) (b) [GeV < y < [GeV LHCf (stat.+syst.) DPMJE.06 QGSJE II-04 SIBYLL 2.1 PYHIA EPOS LHC [GeV xerimental combined sectra of the LHCf detector (filled circles) in + coll ate the total statistical and systematic uncertainties. he redictions of hadron on (see text for details.) 15 σ/d Ed E

18 Neutral hadron (neutron) Energy S=7 ev η> <η< <η<8.99 folded unfolded dmjet Phys. Lett. B 750 (2015) 60-66

19 = +Pb at s NN =5.02 ev Arm2 only UPC+QCD, Nuc.Mod.Fac. π 0 event categories in -Pb collisions (Soft) QCD : central and eriheral collisions Ultra eriheral collisions : virtual hoton from rel. Pb collides a roton Central collisions Periheral collisions roton roton Pb imact arameter : b Pb Momentum distribution of the UPC induced secondary articles is estimated as 1. energy distribution of virtual hotons is estimated by the Weizsacker Williams aroximation. 2. hoton-roton collisions are simulated by the SOHIA model (Eγ > ion threshold).. roduced mesons and baryons by γ- collisions are boosted along the roton beam. roton rest frame Dominant channel to forward π 0 is About half of the observed π 0 may originate in UPC, another half is from soft-qcd. Break down of UPC Comarison with soft-qcd 8 17

20 Pz sectrum of π 0 in +Pb at snn=5.02 ev Ex. data vs model (both include UPC) [GeV 1-1 (a) 0.0 < [GeV < 0.2 (b) 0.2 < [GeV < 0.4 (c) 0.4 < [GeV < 0.6 σ/d Ed inel - -4 LHCf s NN =5.02eV -1 Ldt=0.6nb UPC EPOS-LHC DPMJE.06 EPOS-LHC UPC DPMJE.06 1/σ -5 QGSJEII-04 QGSJEII-04 1 (d) 0.6 < [GeV < 0.8 (e) 0.8 < [GeV < 1.0 [GeV σ/d Ed inel LHCf (stat.+syst.) UPC + DPMJE.06 UPC + QGSJE II-04 UPC + EPOS LHC 1/σ -5 UPC [GeV z [GeV 18 z submitted to PRD

21 -1 Scaling or Limiting Fragmentation (a) 0.0 < [GeV < 0.2 (b) 0.2 < [GeV < 0.4 F dσ/dx Scaling or Limiting Fragmentation inel x F /σ LHCf LHCf s=7ev s=2.76ev 17 Leading exonent α LHCf ( LHCf ( LHCf ( X F s=7ev) s=2.76ev) s NN =5.02eV) = 1 in x F X F Scaling: 2.76 ~ 7.0 ev ~20 % 1 ev RHICf exeriment d dx F (1 x F ) FIG. 15 Premature to discuss saturation Effect? (Strikman) 1 ev with ALAS info [GeV

22 s=1 ev Our main target Data taking: Early Jun Analysis on-going 20

23 0 4 0 s = 7 ev y20 s = 1 ev Jun. 1 y2015 Events 2 Eπ0 > 600GeV Eη >2.2eV M γ γ [MeV At 1 ev, larger accetance for η η itself is insensitive to the A.S develoment; However, Nπ0/Nη deends on interaction models. s=1 ev data will tell it. 21

24 Common DAQ with ALAS 9M events (E>0GeV) Info. related to single/double diffraction will be obtained. 22

25 rial of common DAQ with ALAS in Pb 5.02 ev case dn/ds (events/mm ) ALAS-LHCf, -Pb s NN =5.02eV Hadron like, E>500GeV w/o selection N charged >0 MC (UPC+QCD) MC (QCD) ALAS η=.6 Scattering angle (µrad) Nch ALAS dros most of 2

26 selected selected events events that that DO DO NO NO satisfy satisfy the the ND ND conditions conditions (ND). (ND). PYHIA MC 14 ev. Diffractive event selection efficiency and found found that that 5 5 and and % of of diffractive diffractive evs survive evts survive All events after after ND ND lection ection for for L L and and, resectively resectively in MC true,. We We γ o found found Non-diffractive that that about about % of of Diffractive ND ND selected selected ents nts are are diffractive diffractive cording ording to to PYHIA PYHIA urity:droing events with (P > 0 MeV/c & Nch>1 in η w/ event selection (not ND) For diff. events, 5-40% efficiency 99 % urity mmary key: low mass diffraction (Ostachenko) γ ~ 1 % Energy sectra of hotons and neutrons to be observed by LHCf are shown in n left and below,resectively. he to anels show the sectra of large tower (L) and small tower (S) in left and right anels, resectively. Events are classified in diffractive (red) and nondiffractive(green) according to PYHIA. he bottom n anels show the sectra after event selection using the ALAS information. Non-Diffractive (ND) of ALAS is 24defined as more than 1 charged By Menjo

27 Pi + P info. at higher energies could be obtained: Use neutron tag in LHCf to measure π+ in ALAS From R. Engel /. Pierog relace γ by Arm2 & ALAS Arm1 25

28 Summary Cosmic ray eole, more or less, on the rails. i.e, Models not erfect but not so bad. Pi0 and hoton LHC tuned QGSJEII-4 and EPOS-LHC are fairly good DPMJE: too hard 2ry (PYHIA too) But at X < 0.5 (imortant for A.S) fairly good. Pb case: such tendency increases Leading neutron Very forward region: ~qgsjetii. Others too small yeild Larger angle region: dmjet fairly good. Some hint for model construction 26

29 Summary (cont) UHECR Comosition: further refined model selection or further model tuning. S=1 ev data +ALAS: (low M) diff. Pion int. LHCf data + η< 8.4: e.g CASOR. Albrow) Future SAS (Mike RHICf: test scaling feature Nucleus effect (Air is not ). A AA at LHC?