Overview and recent results of LHCf Takashi SAKO (KMI/ISEE, Nagoya - PowerPoint PPT Presentation

Overview and recent results of LHCf Takashi SAKO (KMI/ISEE, Nagoya University) for the LHCf CollaboraCon 1 26-Oct-2015 TeVPA 2015, Kashiwa

HECR Composi+on TA, APP 64, 49-62 (2015) PAO, PRD 90, 122005 (2014) ü Air shower observaCons determine <X max > vs. energy ü Model predicCons to be compared differ at the level of experimental uncertainCes ü Models must be tested by accelerator experiments 2

Cosmic-ray spectrum and collider energy （ D’Enterria et al., APP, 35,98-113, 2011 ） RHIC LHC FCC End of galac+c CR and transi+on to extra-gal CR Ankle (GZK) cutoff: end of CR spectrum Knee: end of galac+c proton CR 3

LHC Era (T.Pierog, HESZ2015) LHC Tevatron ü Good agreement between post-LHC models, QGS II-04 and EPOS-LHC ü No update in SIBYLL, but very good agreement with the others. By chance??? 4

Parameters to characterize hadronic interac+on 1. σ ine （λ int ） 2. ParCcle producCon MulC meson producCon Leading baryon π - inelasCcity (E meson /E 0 = 1-elasCcity) elasCcity (E baryon /E 0 ) mulCplicity π + Baryon spectrum Meson spectrum π 0 (Baryon-Baryon producCon) 4. π–A interacCon 3. Nuclear effect γ 5 nucleon

Parameters to characterize hadronic interac+on 1. σ ine （λ int ） 2. ParCcle producCon MulC meson producCon Leading baryon π - inelasCcity (E meson /E 0 = 1-elasCcity) elasCcity (E baryon /E 0 ) mulCplicity π + Baryon spectrum Meson spectrum π 0 (Baryon-Baryon producCon) 4. π–A interacCon 3. Nuclear effect γ 6 nucleon

Forward Par+cle Produc+on (photons ≅ π 0 -> γγ) η =7 ü √ s=14 TeV p-p collision (QGSJET II-03) ü Typical p T ≈1GeV/c => high-E parCcles are emiped forward pseudorapidity: η = -ln(tan(θ/2)) 7

Forward Par+cle Produc+on (photons ≅ π 0 -> γγ) η =7 ü √ s=14 TeV p-p collision (QGSJET II-03) ü Typical p T ≈1GeV/c => high-E parCcles are emiped forward LHCf coverage η =8.4 => θ = 440 μrad 8

The LHCf Collabora+on *,** Y.Itow, * Y.Makino, * K.Masuda, * Y.Matsubara, * E.Matsubayashi, *** H.Menjo, * Y.Muraki, * Y.Okuno , *,** T.Sako, * M.Ueno, * Q.D.Zhou * Institute for Space-Earth Environmental Research, Nagoya University, Japan ** Kobayashi-Maskawa Institute, Nagoya University, Japan *** Graduate School of Science, Nagoya University, Japan K.Yoshida Shibaura Institute of Technology, Japan T.Iwata, K.Kasahara, T.Suzuki, S.Torii Waseda University, Japan Y.Shimizu, T.Tamura Kanagawa University, Japan N.Sakurai Tokushima University, Japan M.Haguenauer Ecole Polytechnique, France W.C.Turner LBNL, Berkeley, USA O.Adriani, E.Berti, L.Bonechi, M.Bongi, G.Castellini, R.D’Alessandro, P.Papini, S.Ricciarini, A.Tiberio INFN, Univ. di Firenze, Italy A.Tricomi INFN, Univ. di Catania, Italy A-L.Perrot CERN, Switzerland 9

The LHC forward experiment LHCf Arm#1 ATLAS 140m Two independent detectors at either side of IP1 (Arm#1, Arm#2 ) Beam Beam pipe Charged parCcles (+) LHCf Arm#2 Neutral 96mm par+cles Charged parCcles (-) ü All charged parCcles are swept by dipole magnet ü Neutral parCcles (photons and neutrons) arrive at LHCf ü η>8.4 (to infinity) is covered 10

LHCf Detectors ü Imaging sampling shower calorimeters ü Two calorimeter towers in each of Arm1 and Arm2 ü Each tower has 44 r.l. of Tungsten,16 sampling scinCllator and 4 posiCon sensiCve layers Arm#1 Detector 20mmx20mm+40mmx40mm 4 XY SciFi+MAPMT Arm#2 Detector 25mmx25mm+32mmx32mm 4 XY Silicon strip detectors 11

Detector performance Arm2 Δ E/E ≈ 40% Δ E/E < 5% 12

LHCf Opera+on History • 2009-2010 – Data taking with 900 GeV p-p collisions – Data taking with 7 TeV p-p collisions • 2013 (only Arm2) – Data taking with 5.02 TeV p-Pb collisions – Data taking with 2.76 TeV p-p collisions • 2015 – Data taking with 13 TeV p-p collisions 13

Publica+ons Neutron Photon π 0 (limited π 0 (full (hadron Performance (EM shower) acceptance) acceptance) shower) NIM, A671 JINST, 9 (2014) Beam test (2012) P03016 129-136 PLB, 715 0.9TeV p-p (2012) 298-303 IJMPA, 28 (2013) 1330036 PLB, 703 PLB, 750 PRD, 86, 7TeV p-p (2011) (2015) (2012) 092001 128-134 360-366 PRD submihed 2.76TeV p-p PRC, 89 (2014) 065209 5.02TeV p-Pb 13TeV p-p Analysis in progress physics results performance results 14

Forward neutron spectra in 7TeV p-p collisions (√s=7TeV p-p ； PLB 750 (2015) 360-366) zero degree ü Zero degree producCon is qualitaCvely explained by QGSJET II ü Non-zero-degree producCons (larger cross secCon) are underesCmated by popular QGSJET II and EPOS models 15

π 0 p z spectra in 7TeV p-p collisions (PRD submiped,arXiv:1507.08764 [hep-ex]) (a) 0.0 < p [GeV] < 0.2 (b) 0.2 < p [GeV] < 0.4 (c) 0.4 < p [GeV] < 0.6 ] T T T 1 -2 [GeV 1 − 10 3 − 2 /dp 10 σ 3 − 10 3 LHCf s =7TeV Ed ∫ -1 Ldt=2.64+2.85nb − 4 inel 10 σ − 5 1/ 10 (d) 0.6 < p [GeV] < 0.8 (e) 0.8 < p [GeV] < 1.0 T T ] 1 -2 [GeV 1 − LHCf (stat.+syst.) 10 3 DPMJET 3.06 − 2 /dp 10 QGSJET II-04 σ 3 − 3 10 Ed SIBYLL 2.1 4 inel − 10 PYTHIA 8.185 σ 1/ − 5 10 EPOS LHC 1000 2000 3000 1000 2000 3000 p [GeV] p [GeV] z z 16

Energy flow in 7TeV p-p collisions ü Post-LHC models (EPOS-LHC and QGSJET II-04) well explain the π 0 results, but not for neutrons ü DPMJET3 explains the neutron results, but it is not recently used for CR simulaCons neutron π 0 LHCf Zero degree DPM3 QGS II-04 EPOS-LHC pseudo-rapidity (η) rapidity (y) to be covered in 13TeV Black solid circle : LHCf data (π 0 , LHCf 2012) Doped lines : π 0 energy flow distribuCon of each model Thick horizontal line : Energy flow calculaCon a|er p T cut 17

√s scaling of π 0 produc+on ü (630GeV −) 2.76TeV – 7TeV good scaling within uncertaintes ü W ider coverage in y and p T with 13TeV data ü Wider √s coverage with RHICf experiment in 2017 at √s=510GeV 18

√s scaling of π 0 produc+on ü (630GeV −) 2.76TeV – 7TeV good scaling within uncertaintes ü W ider coverage in y and p T with 13TeV data ü Wider √s coverage with RHICf experiment in 2017 at √s=510GeV 19

13TeV opera+on in June 2015 • LHCf physics fills: 10-13 June 2015 • Total physics data taking: 26.6 hours • Observed high energy (>100GeV) parCcles : 39M events • π 0 candidates : 0.5 M events 20

13TeV opera+on in June 2015 2TeV π 0 by Arm2 21

13TeV opera+on in June 2015 2TeV π 0 by Arm2 22

Joint analysis with ATLAS Well studied by big experiments Invisible for big experiment but having high energy PYTHIA8 s imulaCon All LHCf events (mixture of diffracCon and ND) N Non_diff+Diff 18000 Non_diff Diff MC True; non-diffracCon (ND) 16000 Diff-like 14000 MC True; diffracCon 12000 10000 LHCf events selected using ATLAS informaCon, 8000 6000 same shape to the TRUE diffracCon events 4000 2000 23 0 0 1000 2000 3000 4000 5000 6000 7000 8000 E[GeV]

Summary Collider data improve the hadronic interacCon models used in the cosmic- ü ray studies LHCf measures forward parCcle spectra, both baryons and mesons, carrying ü a large fracCon of collision energy LHCf π 0 spectra are well explained by the post-LHC models, EPOS-LHC • and QGSJET II-04 LHCf neutron spectra show excess, 30% in energy flow, than the post- • LHC models LHCf confirmed scaling of π 0 producCon at 2.76 TeV and 7 TeV data, • but in a limited phase space ü 13TeV data taking in 2015 was successful Scaling test with wider phase space at the highest energy • More insight to the process by collaboraCng with ATLAS • ü Low energy extension at RHIC is scheduled in 2017 Wider √s coverage for scaling test => important to access >10 17 eV • 24