Current status of the LHCf experiment Yasushi Muraki (Konan University) 1. A history on hadron physics 2. Previous experiment CERN UA7 3. Current experiment a ｔ LHC: LHCf Measurement of π 0 cross-section emitted in a very forward region by the pp collisions at E 0 =10 17 eV

Historical debate in the field of cosmic ray physics Around 1980, there was a big debate in the field of cosmic ray physics Whether or not the nuclear interaction process is changing at 100 TeV? Or it just reflects an increase of heavy primary component like Fe in the primary component of cosmic rays. The data showed only rapid development of the cascade showers in the atmosphere.

A typical example of such a debate: Chacaltaya emulsion group → new interaction process like Centauro Fuji-Tibet group: increase of iron component If we can launch again a new heavy calorimeter in the space, we can resolve this problem immediately, but the experiment is very expensive in Moscow conference..

1981

The CERN UA7 experiment , Muraki, M. Haguenauer(UA4) et al.

Roman pot and Silicon calorimeters are used

The energy is calibrated by π 0 peak Eric Paré et al, Phys. Lett. B242 (1990) 531.

Result : Feynman scaling does hold at very forward region at 150TeV

New debate in the very high energy region We must need again by an accelerator experiment. To establish the GZK cut-off problem, we need a calibration experiment. To calibrate the Monte Carlo Codes that are often used for the reduction of the incident energy of air showers at LHC.

The position of shower maximum Knapp et al, Astroparticle Physics, 19(2003) 77 UA7 LHCf Fe incidence

How to do it?

Detector location Y Chamber

LHCf two kinds of tower calorimeter Arm#1Arm#2 W plates Scintillator SciFi x-y layerSi microstrip x-y layer 25cm

Arm#1 during assembly Tower calorimeters Light guides 32 PMTs + 8 MAPTs

independent detectors on both sides of IPX independent detectors on both sides of IPX INTERACTION POINT Beam line Detector II Tungsten Scintillator Silicon  strips Detector I Tungsten Scintillator Scintillating fibers 140 m 1.Redundancy 2.Background rejection (especially beam-gas) 3.Physics single diffractive/double diffractive

Transverse projection of LHCf and beam pipe acceptance (coverage)

Two calorimeters are lifted up and down by the manipulators IP1 140m away TAN LHCf Arm#1

Monte Carlo  ray energy spectrum 10 6 generated LHC interactions  1 minute exposure

K.Fukui, Y.Itow, T.Mase, K.Masuda, Y.Matsubara, H.Menjo, T.Sako, K.Taki Solar-Terrestrial Environment Laboratory, Nagoya University, Japan K.Yoshida Shibaura Institute of Technology, Japan K.Kasahara, M.Mizuishi, S.Torii Waseda University, Japan T.Tamura Kanagawa University, Japan Y.Muraki Konan University Y.Shimizu ICRC, University of Tokyo, Japan M.Haguenauer Ecole Polytechnique, France W.C.Turner LBNL, Berkeley, USA O.Adriani, L.Bonechi, M.Bongi, R.D’Alessandro, M.Grandi, P.Papini, S.Ricciarini, G.Castellini, A. Viciani INFN, Univ. di Firenze, Italy A.Tricomi INFN, Univ. di Catania, Italy J.Velasco, A.Faus IFIC, Centro Mixto CSIC-UVEG, Spain D.Macina, A-L.Perrot CERN, Switzerland The LHCf experiment (Apr )

IP1, ATLAS, LHCf IP5, CMS IP2, ALICE IP8, LHCb

Current status of the LHCf experiment The two detectors have been installed now at the collision point IP1. The beam will circulate in the 28km tunnel on September 10th (Today! ). The beams will make collisions within one month. The beams will be accelerated to 5TeV until the end of this year. √ s=10 TeV

September 10 Before we startBeam down the lines to the TEDs OK (check to TDIs) All screens in and visible (or easily made so) Synoptic display and trajectory display Primary aim: Get protons round ring 1 Get protons round ring 2 Aperture ~clear in both rings Icing: Inject and dump after > 1 turn Interleaved injection into both rings (as we did Sunday 24th) Dreaming: Get 5 109protons to circulate in ring 1 Get 5 109protons to circulate in ring R.Bailey, September 2008

By R.Bailey, September 2008

Concluding remarks Concluding Remarks ★ A very important data will be obtained without change of present LHC projects. ★ The data will become extremely useful not only for cosmic ray physics, but also for high energy physics. ★ The data will be used for a long time. Other remarks ＊ We also want to measure N-N or p-N or or N-Fe collisions. ( N= N 2 and O 2 ) ＊ We also get another important data on neutrons and K 0 s and the inelesticity.

We can measure the region of photons with X F >0.05 by this experiment.

The position of shower maximum Knapp et al, Astroparticle Physics, 19(2003) 77 UA7 LHCf Fe incidence

The background The beam gas contamination We estimate beam-beam: beam-gas = 2 : L= and early stage but at the later stage = 1: L= and later stage At the beginning, taking account of the acceptance for the beam-gas event by the M.C. calculation, we found that the ratio between beam-beam : beam-gas = 10 : 1 (contamination is ~10%) However if we will take arm#1*arm#2 trigger, it will be reduced to 1000:1. Unfortunately a that time we may loose pure single diffractive event. Therefore we must repeat the data-taking after machine conditioning. However the above value is estimated for the high luminosity case and in fact in the early low luminosity case, the gas in the beam pipe would be not so much. We must ask a calculation to the CERN vacuum group.

Two production cross-sections were assumed for Monte Carlo : A and B.

We have made a similar detector what we had proposed and made a test experiment using NA beam line of CERN. The detector was bombarded to the electron, muon and proton beams with energies GeV. The position of the beam incidence was measured by the silicon detector.

At 140m away from the interaction region there is a gap of 9cm that can put a small calorimeter IP, +140m Instrumentation slot (96mm x 60.7mm x 1000mm) ~ 5m

We could install an electromagnetic calorimeter there