LHCf: stato e programmi Oscar Adriani CSN1,Torino, 27 settembre 2012

Introduction and contents Analyses 0 paper accepted by PRD 900 GeV paper published on PLB Short spot on other analyses Arm1 preparation for 14 TeV Beam test at SPS (August-September 2012) Arm2 preparation for p/Pb 2013 run

LHCf: location and detector layout 44X 0, 1.6 int INTERACTION POINT IP1 (ATLAS) Detector II TungstenScintillator Silicon strips Detector I TungstenScintillator Scintillating fibers 140 m n π0π0 γ γ 8 cm6 cm Front Counter Arm#1 Detector 20mmx20mm+40mmx40mm 4 X-Y SciFi tracking layers Arm#2 Detector 25mmx25mm+32mmx32mm 4 X-Y Silicon strip tracking layers

π 0 analysis: P T spectra for different rapidity bins Measurement of forward neutral pion transverse momentum spectra for s = 7TeV proton-proton collisions at LHC Accepted by PRD

Type-I Type-II Type-II at small tower Type-II at large tower Type-I LHCf-Arm1 Type-II LHCf-Arm1 LHCf-Arm1 Data 2010 BG Signal Preliminary Large angle Simple Clean High-stat. Small angle large BG Low-stat., but can cover High-E Large-P T π 0 analysis at s=7TeV Submitted to PRD (arXiv: ).

Type I π 0 analysis procedure Mass, energy and transverse momentum are reconstructed from the energies and impact positions of photon pairs measured by each calorimeter Analysis Procedure Standard photon reconstruction Event selection - one photon in each calorimeter - reconstructed invariant mass Background subtraction by using outer region of mass peak Unfolding for detector response. Acceptance correction. Dedicated part for π 0 analysis I.P.1 1 (E 1 ) 2 (E 2 ) 140m R

Acceptance for π 0 at LHCf-Arm1 Validity check of unfolding method Remaining background spectrum is estimated using the sideband information, then the BG spectrum is subtracted from the spectrum obtained in the signal window. Raw distributions are corrected for detector responses by an unfolding process that is based on the iterative Bayesian method. (G. D Agostini NIM A 362 (1995) 487) Detector response corrected spectrum is then corrected for acceptance LHCf-Arm1 s=7TeV 9.0<y<11.0 True EPOS Unfolded(by π 0 +EPOS) Unfolded(by π 0 +PYTHIA) Measured EPOS Acceptance and unfolding Submitted to PRD (arXiv: ).

π 0 results: Data vs MC

π 0 results: Data/MC Submitted to PRD (arXiv: ).

Data/MC commented dpmjet 3.04 & pythia show overall agreement with LHCf data for 9.2<y<9.6 and p T <0.25 GeV/c, while the expected production rates by both models exceed the LHCf data as p T becomes large sibyll 2.1 predicts harder pion spectra than data, but the expected yield is generally small qgsjet II-03 predicts spectra softer than LHCf data epos 1.99 shows the best overall agreement with the LHCf data. behaves softer in the low p T region, p T < 0.4GeV/c in 9.0<y<9.4 and p T <0.3GeV/c in 9.4<y<9.6 behaves harder in the large p T region.

distribution Three different approaches used to derive the average transverse momentum, pT 1.by fitting an empirical function to the p T spectra in each rapidity range (exponential distribution based on a thermodynamical approach) 2.By fitting a gaussian distribution 3.by simply numerically integrating the p T spectra Results of the three methods are in agreement and are compared with UA7 data and hadronic model predictions. Two UA7 and LHCf experimental data show the same trend no evident dependence of on E CM S. Y Beam =6.5 for SPS Y Beam =8.92 for7 TeV LHC

900 GeV inclusive spectra Measurement of zero degree single photon energy spectra for s = 900 GeV proton-proton collisions at LHC PLB 715 (2012) 298 CERN-PH-EP

Comparison wrt MC Models at 900 GeV

small-η = Large tower big-η =Small tower analysis: Comparison btw 900 GeV and 7 TeV spectra Coverage of the photon spectra in the plane Feynman-X vs P T

small-η = Large tower big-η =Small tower A jump back to analysis: Comparison btw 900GeV and 7TeV spectra Coverage of the photon spectra in the plane Feynman-X vs P T 900GeV vs. 7TeV with the same PT region 900 GeV Small+large tower

small-η = Large tower big-η =Small tower A jump back to analysis: Comparison btw 900GeV and 7TeV spectra Normalized by the number of entries in X F > 0.1 No systematic error is considered in both collision energies. X F spectra : 900GeV data vs. 7TeV data Good agreement of X F spectrum shape between 900 GeV and 7 TeV. weak dependence of on E CMS Preliminary Data 2010 at s=900GeV (Normalized by the number of entries in X F > 0.1) Data 2010 at s=7TeV (η>10.94) Coverage of the photon spectra in the plane Feynman-X vs P T 900GeV vs. 7TeV with the same PT region 900 GeV Small+large tower

Neutron and K 0 (very preliminary…) analyses

Why neutron measurement is important for CR physics Auger hybrid analysis event-by-event MC selection to fit FD data (top plot) comparison with SD data vs MC (bottom plot) Clear muon excess in data even for Fe primary MC The number of muons increases with the increase of the number of baryons! => importance of direct baryon measurement

Neutron Detection Efficiency and energy linearity Efficiency at the offline shower trigger Flat efficiency >500GeV % Linear fit Parabolic fit

Energy and Position Resolution X Y Neutron incident at (X,Y) = (8.5mm, 11.5mm) ~1mm position resolution Weak dependence on incident energy We are trying to improve the energy resolution by looking at the electromagneticity of the event

K 0 analysis

K 0 Acceptance

Status of the LHCf preparation for 14 TeV

LHCf preparation for the 14 TeV p-p run Calorimeter radiation hardening by replacing plastic scintillator with GSO Scintillator plates 3 mm 1mm thick scintillators Acrylic quartz light guides construction and light yield uniformity test carried out in Japan SciFi 1 mm square fibers 1 mm GSO square bars No clad-core structure (GSO bar) Attenuation and cross talk test carried out Acrylic light guide fiber quartz light guide fibers Construction and light yield test carried out Production and laboratory tests of the new scintillators in Japan is finished Beam test at Ion facility (HIMAC) has been done in June 2012 Arm1 has been re-assembled in Florence starting from end of June Same procedure will be followed in 2013 for the Arm2 detector Upgrade of the silicon positioning measurement system Rearranging Silicon layers for independent precise energy measurement Increase the dynamic range to reduce saturation effects

Beam test at the SPS Long beam test has been conducted from August 17 th to September 4 th in the H2 SPS area Muons, GeV electrons, 350 GeV protons More than 1 TB of data Main goals: Energy scale of upgraded Arm1 detector Check of energy scale of not upgraded Arm2 for the p/Pb run Test of the solution to improve the silicon saturation for 14 TeV run Check of the temperature dependence of the absolute energy scale both for Arm1 and Arm2 Very successful beam test!

Test of new silicon pattern bonding Problem: saturation of the silicon electronics for E > 1.5 TeV Pace3 dynamic range is not enough to sustain such a huge energy release Not a problem for TeV runs Software corrections based on the different PACE3 samples allow to increase saturation up to 2.5/3 TeV Become an issue for 7+7 TeV run We will change the silicon sensors position to improve the silicon only energy resolution…. We developed a new idea to hardware improve the saturation level

Silicon sensor Not used Normal configuration New configuration Readout Floating Readout Ground Arm2 detector New silicon Pb (40mm) e-, 200 GeV/c Different silicon bonding scheme The beam test setup 80 m implant pitch 160 m readout pitch

New Silicon Module results (Quick analysis) Clearly the pulse height in the region of new configuration were reduced by a factor of 1.5 ~ 1.7 (we could naively expect 2) The modification works fine to enlarge the silicon dynamic range #Strip NormalNew Silicon Lateral distribution Histogram of peak values

Arm2 Pi0 Mass v.s. Temperature at LHC 15-Mar / 31-Mar-2012 Remember the 3.8% Mass Shift that was longly discussed….

Temperature test and control at SPS During the beam test, we carefully controlled the temperature of the detector with a chiller We waited for some hours until the temperature was very stable (< 0.1 degree / hour) Water

Temperature test (Arm2) Check the temperature dependency of the energy scale by changing the chiller temperature to 18, 23, 28, 33 degrees Chiller temperature Thermometer in Arm2

Energy scale temperature dependence(Arm2) The temperature coefficient is consistent with the R7400U catalog value (-0.20% /C) We could confirm that there is a dependence of energy scale on the temperature. Compatible with 3.8% mass shift???? To be checked

Re-installation for the p/Pb run Arm2 will be re-installed in the TAN during the technical stop foreseen at the end of the p/p run We have modified the LHCf support structure and cabling to significantly reduce the installation required time The procedure for reinstallation has been carefully discussed in the LTEX meetings and is ready Checked with RP RP gave green light We are continuing discussions with ATLAS for trigger and data exchange, to get the maximum physics outcome for the data, following the LHCC recommendation Arm2 will be brought back to Florence after the p/Pb run completion (special transport will be necessary because of the slight radioactivity)

Miscellanea…. I Possibility to use LIGHT IONS in LHC from 2016/2017? Light Ion source setup is ongoing because of SPS interest RHIC run in 2015/2016 was under discussion… Please stand by a little bit to see how things are evolving!!!! We have a new Japanese expert post doc that will stay in Italy for 2 years paid by Japan

Miscellanea II: Working together with MC model developers Since the first paper we are in strict connection with model developers (EPOS,QGSJET, SYBILL etc.) We have taken part to several meetings/workshops We are contributing to the tuning of the model to LHCf data We are also involved in the MCPLOTS/RIVET project ( a simple browsable repository of MC (Monte Carlo) plots comparing High Energy Physics event generators to a wide variety of available experimental data, for tuning and reference purposes

Miscellanea III: Working together with other LHC MC contacts Since last year we are involved in one of the WG of the MC4LHC project A new WG is now starting to focus on astroparticle physics connection with contact persons from each LHC experiments A. Tricomi, T. Sako Set up and organize a workshop

Miscellanea IV: LHCf computing Lo scorso anno abbiamo presentato un piccolo modello di calcolo per far fronte alle esigenze di simulazione e ricostruzione di LHCf per il run p-Pb di cui siamo responsabili I referee ci hanno finanziato una parte di quello richiesto rimandando a questanno la seconda parte a fronte di stime più precise per consentirci la produzione dei plot per la LOI Il data set per la LOI è stato prodotto interamente in Italia e le tre macchine acquistate sono state fondamentali Abbiamo fatto i primi test di simulazione completa con p-Pb 500 KB per evento e 570 sec/evento con la simulazione completa 20 KB per evento e 22 sec/evento se applichiamo dei tagli cinematici abbastanza duri (eccessivi per quello che vorremmo fare) Una via di mezzo tra queste due, dell'ordine dei 100 KB e 100 sec/evento e' quella piu' realistica senza perdere informazioni di fisica rilevanti. Noi abbiamo bisogno di produrre come minimo 10 7 eventi per ciascuno dei modelli studiati (finora 5) Poichè le stime dello scorso anno, basate sulla sola generazione erano ben più ottimistiche di quello che abbiamo ottenuto ora, chiediamo il completamento delle risorse. Per il disco cercheremo di utilizzare risorse presenti in sezione ma abbiamo bisogno di CPU dedicate 15 Keuro per lacquisto delle CPU

Miscellanea V: Missioni estere Ad Aprile 2012 la CSN1 ci aveva sbloccato 35 kE di Missioni Estere che erano SJ al run p/Pb Dato che il run p/Pb è stato spostato al 2013, restituiamo alla CSN1 27 kE di ME (21 kE da Firenze e 6 kE da Catania) Cerchiamo di effettuare più lavori possibile nel 2012 Setup di control room e DAQ Test di interfaccia con la macchina Installazione meccanica nel tunnel Con la ragionevole speranza che ci vengano riassegnati per il 2013!!!!!!

Conclusions The analysis work is nicely going on Very important and tight contacts with the theorists and the model developers to maximize the outcome of the LHCf results Arm1 upgrade has been completed Arm2 is ready to be installed for the 2013 p/Pb run Very successful test beam has been completed in summer 2012 Arm2 upgrade will be completed in 2013 Ready to take data at 14 TeV And…. Possible Light Ions runs at RHIC/LHC are under investigation

Spares slides

Temperature dependency (Arm1) The temperature dependency has been also checked for Arm1. The coefficient of GSO may be bigger than PMT, about - 0.5% / degree. Compared the histograms of dE in each layer at 18, 23, 28, 33 chiller temperatures. T_Chiller

Layer 03Layer 04 Layer 06Layer 05 The coefficient is between 0.17% degree and 0.45% / degree. Slightly bigger than Arm2, but not so serious.

Fast install/uninstall Silicon strip FE electronics LHCf main detector Calorimeters amplifier To be assembled in a single structure Now 35 BNC connections in the tunnel To be packed in 2- 3 Harting multipoles connectors Now 3 main structures installed separately

Radiation hardness of GSO No decrease up to 1 MGy +20% increase over 1 kGy (τ=4.2h recovery) 2 kGy is expected for 350nb 14TeV pp) kGy Not irradiated ref. sample Irradiated sample τ~4.2h recovery K. Kawade et al., JINST, 6, T09004, 2011 Dose rate=2 kGy/hour (10 32 cm -2 s -1 )

Global LHCf physics program LHCf measurement for p-Pb interactions at 3.5TeV proton energy could be easily and finely integrated in the LHCf global campaign. PeriodType Beam energy LAB proton Energy (eV) Detector 2009p - p GeV Arm1+Arm2 2009/2010p - p TeV Arm1+Arm2 2013p – Pb 3.5 TeV proton E Arm2 2014p - p7+7 TeV10 17 Arm1+Arm2 upgraded

Proton-remnant side – photon spectrum Small tower Big tower

Proton-remnant side – neutron spectrum Small tower Big tower 35% ENERGY RESOLUTION IS CONSIDERED IN THESE PLOTS

Proton remnant side – Invariant cross section for isolated -rays

What LHCf can measure in the p+Pb run (2) Study of the Nuclear Modification Factor Nuclear Modification Factor measured at RHIC (production of 0 ): strong suppression for small p t at =4. LHCf can extend the measurement at higher energy and for >8.4 Very important for CR Physics Phys. Rev. Lett. 97 (2006)

Lead-remnant side – multiplicity Please remind that EPOS does not consider Fermi motion and Nuclear Fragmentation n Small tower Big tower

Minimum required number of collision: N coll = 10 8 (factor 10 more statistics wrt shown plots) Integrated luminosity L int = 50 b single photons expected on p-remnant side expected on same side Assuming a pessimistic scenario with luminosity L = cm -2 s -1 : Minimum running time for physics t = 140 h (6 days) … and required statistics to complete the p/Pb physics run