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Expected Performance of the ATLAS Experiment: Detector, Trigger and Physics

2008-12-31T23:00:00Z

Expected Performance of the ATLAS Experiment: Detector, Trigger and Physics Aad, G.; Bacci, Cesare; Ceradini, Filippo; Di Luise, Silvestro; Diglio, Sara; Orestano, Domizia; Pastore, Fernanda; Petrucci, Fabrizio; Spogli, L.; et, al. 2009-01 The Large Hadron Collider (LHC) at CERN promises a major step forward in the understanding of the fundamental nature of matter. The ATLAS experiment is a general-purpose detector for the LHC, whose design was guided by the need to accommodate the wide spectrum of possible physics signatures. The major remit of the ATLAS experiment is the exploration of the TeV mass scale where ground breaking discoveries are expected. In the focus are the investigation of the electroweak symmetry breaking and linked to this the search for the Higgs boson as well as the search for Physics beyond the Standard Model. In this report a detailed examination of the expected performance of the ATLAS detector is provided, with a major aim being to investigate the experimental sensitivity to a wide range of measurements and potential observations of new physical processes. An earlier summary of the expected capabilities of ATLAS was compiled in 1999. Since that time, the design of the detector has been finalised, and construction and installation have been completed. An extensive test-beam programme was undertaken. Furthermore, the simulation and reconstruction software code and frameworks have been completely rewritten. Revisions incorporated reflect improved detector modelling as well as major technical changes to the software technology. Greatly improved understanding of calibration and alignment techniques, and their practical impact on performance, is now in place. The studies reported here are based on full simulations of the ATLAS detector response. A variety of event generators were employed. The simulation and reconstruction of these large event samples thus provided an important operational test of the new ATLAS software system. In addition, the processing was distributed world-wide over the ATLAS Grid facilities and hence provided an important test of the ATLAS computing system – this is the origin of the expression “CSC studies” (“computing system commissioning”), which is occasionally referred to in these volumes. This report is broadly divided into two parts: firstly the performance for identification of physics objects is examined in detail, followed by a detailed assessment of the performance of the trigger system. This part is subdivided into chapters surveying the capabilities for charged particle tracking, each of electron/photon, muon and tau identification, jet and missing transverse energy reconstruction, b-tagging algorithms and performance, and finally the trigger system performance. The second major subdivision of the report addresses physics measurement capabilities, and new physics search sensitivities. Individual chapters in this part discuss ATLAS physics capabilities in Standard Model QCD and electroweak processes, in the top quark sector, in b-physics, in searches for Higgs bosons, supersymmetry searches, and finally searches for other new particles predicted in more exotic models.

Study of the a0(980) meson via the radiative decay phi -> eta pi0 gamma with the KLOE detector

2009-08-31T22:00:00Z

Study of the a0(980) meson via the radiative decay phi -> eta pi0 gamma with the KLOE detector Ambrosino, Fabio; Bacci, Cesare; Bocchetta, Simona Serena; Ceradini, Filippo; Di Micco, Biagio; Nguyen, Federico 2009-09 Physics Letters B 681 5-13 We have studied the phi-> a0(980) gamma process with the KLOE detector at the Frascati phi-factory DAFNE by detecting the phi -> eta pi0 gamma decays in the final states with η -> gamma gamma and eta -> pi+ pi- pi0. We have measured the branching ratios for both final states: Br(phi -> eta pi0 gamma) = (7.01 ± 0.10 ± 0.20)×10−5 and (7.12 ± 0.13 ± 0.22)×10−5, respectively. We have also extracted the a0(980) mass and its couplings to eta-pi0, K+K−, and to the φ-meson from the fit of the eta-pi0 invariant mass distributions using different phenomenological models.

Scalar mesons with the KLOE experiment

2008-12-31T23:00:00Z

Scalar mesons with the KLOE experiment Ambrosino, Fabio; Bacci, Cesare; Bocchetta, Simona Serena; Ceradini, Filippo; Di Micco, Biagio; Nguyen, Federico 2009-01 Nuclear Physics B Proceedings Supplements 186 290-293 New results concerning the scalar mesons f0(980) produced in the φ → ππγ decays, and the a0(980) scalar mesons in the φ → a0(980)γ → ηπ0γ decays, are presented.

Calibration and performances of the KLOE calorimeter

2008-12-31T23:00:00Z

Calibration and performances of the KLOE calorimeter Ambrosino, F.; Antonelli, A.; Antonelli, M.; Archilli, F.; Bacci, Cesare; Beltrame, P.; Bencivenni, G.; Bertolucci, S.; Bini, C.; Bloise, C.; Bocchetta, Simona Serena; Bossi, F.; Branchini, Paolo; Campana, P.; Capon, G.; Capussela, T.; Ceradini, Filippo; Chi, S.; Chiefari, G.; Ciambrone, P.; Crucianelli, F.; De Lucia, E.; De Santis, A.; De Simone, P.; De Zorzi, G.; Denig, A.; Di Domenico, A.; Di Donato, C.; Di Micco, Biagio; Doria, A.; Dreucci, M.; Felici, G.; Ferrari, A.; Ferrer, M. L.; Fiore, S.; Forti, C.; Franzini, P.; Gatti, C.; Gauzzi, P.; Giovannella, S.; Gorini, E.; Graziani, E.; Kluge, W.; Kulikov, V.; Lacava, F.; Lanfranchi, G.; Lee-Franzini, J.; Leone, D.; Martini, M.; Massarotti, P.; Mei, W.; Meola, S.; Miscetti, S.; Moulson, M.; Mueller, S.; Murtas, F.; Napolitano, M.; Nguyen, Federico; Palutan, M.; Pasqualucci, E.; Passeri, Antonio; Patera, V.; Perfetto, F.; Primavera, M.; Santangelo, P.; Saracino, G.; Sciascia, B.; Sciubba, A.; Sibidanov, A.; Spadaro, T.; Testa, M.; Tortora, Ludovico; Valente, P.; Venanzoni, G.; Versaci, R.; Xu, G. 2009-01-01 Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment 598 239-243 The KLOE experiment uses a fine sampling lead-scintillating fibrecalorimeter to measure energy, time and position of neutral and charged particles. The overall detector consists of 88 modules organised in a barrel and two end-caps, for a total granularity of 2440 cells, read-out by photo-multipliers at both fibre ends. The chosen design of a high sampling fraction with the usage of thin lead layers and fast scintillating fibres allows to reach good efficiency for photonenergies down to few MeV, good energy resolution and excellent time resolution. The design, calibration and performances of the calorimeter on efficiency, time/position/energy resolution and particle identification is reviewed. The overall calorimeter impact on kaon tagging and on physics results is also presented.

Temperature effect on RPC performance in the ARGO-YBJ experiment

2009-08-31T22:00:00Z

Temperature effect on RPC performance in the ARGO-YBJ experiment Aielli, G.; Bacci, Cesare; Bartoli, B.; Bernardini, P.; Bi, X. J.; Bleve, C.; Branchini, Paolo; Budano, Antonio; Bussino, Severino; Calabrese Melcarne, A. K.; Camarri, P.; Cao, Z.; Cappa, A.; Cardarelli, R.; Catalanotti, S.; Cattaneo, C.; Celio, Paola; Chen, S. Z.; Chen, Y.; Cheng, N.; Creti, P.; Cui, S. W.; Dai, B. Z.; D'Ali Staiti, G.; Danzengluobu; Dattoli, M.; De Mitri, I.; D'Ettorre Piazzoli, B.; De Vincenzi, Mario; Di Girolamo, T.; Ding, X. H.; Di Sciascio, G.; Feng, C. F.; Feng, Zhaoyang; Feng, Zhenyong; Galeazzi, Fulvio; Galeotti, P.; Gargana, Riccardo; Gou, Q. B.; Guo, Y. Q.; He, H. H.; Hu, Haibing; Hu, Hongbo; Huang, Q.; Iacovacci, M.; Iuppa, R.; James, Irina; Jia, H. Y.; Labaciren; Li, H. J.; Li, J. Y.; Li, X. X.; Liberti, B.; Liguori, G.; Liu, C.; Liu, C. Q.; Liu, M. Y.; Liu, J.; Lu, H.; Ma, X. H.; Mancarella, G.; Mari, Stefano Maria; Marsella, G.; Martello, D.; Mastroianni, S.; Meng, X. R.; Montini, Paolo; Ning, C. C.; Pagliaro, A.; Panareo, M.; Perrone, L.; Pistilli, Pio; Qu, X. B.; Rossi, E.; Ruggieri, Federico; Saggese, L.; Salvini, P.; Santonico, R.; Shen, P. R.; Sheng, X. D.; Shi, F.; Stanescu, Cristian; Surdo, A.; Tan, Y. H.; Vallania, P.; Vernetto, S.; Vigorito, C.; Wang, B.; Wang, H.; Wu, C. Y.; Wu, H. R.; Xu, B.; Xue, L.; Yan, Y. X.; Yang, Q. Y.; Yang, X. C.; Yuan, A. F.; Zha, M.; Zhang, H. M.; Zhang, JiLong; Zhang, JianLi; Zhang, L.; Zhang, P.; Zhang, X. Y.; Zhang, Y.; Zhaxisangzhu; Zhou, X. X.; Zhu, F. R.; Zhu, Q. Q.; Zizzi, G. 2009-09 Nuclear Instruments & Methods in Physics Research. Section A 608 246-250 The ARGO-YBJ experiment has been taking data for nearly 2 years. In order to monitor continuously the performance of the Resistive Plate Chamber detectors and to study the daily temperature effects on the detector performance, a cosmic ray muon telescope was setup near the carpet detector array in the ARGO-YBJ laboratory. Based on the measurements performed using this telescope, it is found that, at the actual operating voltage of 7.2kV, the temperature effect on the RPC time resolution is about 0.04ns/degrees C and on the particle detection efficiency is about 0.03%/degrees C. Based on these figures we conclude that the environmental effects do not affect substantially the angular resolution of the ARGO-YBJ detector.

Software timing calibration of the ARGO-YBJ detector

2008-12-31T23:00:00Z

Software timing calibration of the ARGO-YBJ detector Aielli, G.; Bacci, Cesare; Bartoli, B.; Bernardini, P.; Bi, X. J.; Bleve, C.; Branchini, P.; Budano, A.; Bussino, Severino; Calabrese Melcarne, A. K.; Camarri, P.; Cao, Z.; Cappa, A.; Cardarelli, R.; Catalanotti, S.; Cattaneo, C.; Cavaliere, S.; Celio, Paola; Chen, S. Z.; Cheng, N.; Creti, P.; Cui, S. W.; Cusumano, G.; Dai, B. Z.; D'Ali Staiti, G.; Danzengluobu; Dattoli, M.; De Mitri, I.; D'Ettorre Piazzoli, B.; De Vincenzi, Mario; Di Girolamo, T.; Ding, X. H.; Di Sciascio, G.; Feng, C. F.; Feng, Zhaoyang; Feng, Zhenyong; Ferrigno, C.; Galeazzi, Fulvio; Galeotti, P.; Gao, X. Y.; Gargana, Riccardo; Gou, Q. B.; He, H. H.; Hu, Haibing; Hu, Hongbo; Huang, Q.; Iacovacci, M.; James, I.; Jia, H. Y.; Labaciren; Li, H. J.; Li, J. Y.; Liberti, B.; Liguori, G.; Liu, C. Q.; Liu, J.; Lu, H.; Mancarella, G.; Mari, Stefano Maria; Marsella, G.; Martello, D.; Mastroianni, Stefano; Meng, X. R.; Mu, J.; Nicastro, L.; Ning, C. C.; Palummo, L.; Panareo, M.; Perrone, L.; Pino, C.; Pistilli, Pio; Qu, X. B.; Rossi, E.; Ruggieri, Federico; Saggese, L.; Salvini, P.; Santonico, R.; Segreto, A.; Shen, P. R.; Sheng, X. D.; Shi, F.; Stanescu, Cristian; Surdo, A.; Tan, Y. H.; Vallania, P.; Vernetto, S.; Vigorito, C.; Wang, H.; Wang, Y. G.; Wu, C. Y.; Wu, H. R.; Xu, B.; Xue, L.; Yang, H. T.; Yang, Q. Y.; Yang, X. C.; Yu, G. C.; Yuan, A. F.; Zha, M.; Zhang, H. M.; Zhang, J. L.; Zhang, L.; Zhang, P.; Zhang, X. Y.; Zhang, Y.; Zhaxisangzhu; Zhou, X. X.; Zhu, F. R.; Zhu, Q. Q.; Zizzi, G. 2009-01 Astroparticle Physics 30 287-292 The ARGO-YBJ experiment is mainly devoted to search for astronomical gamma sources. The arrival direction of air showers is reconstructed thanks to the times measured by the pixels of the detector. Therefore, the timing calibration of the detector pixels is crucial in order to get the best angular resolution and pointing accuracy. Because of the large number of pixels a hardware timing calibration is practically impossible. Therefore an off-line software calibration has been adopted. Here, the details of the procedure and the results are presented.

Proton-air cross section measurement with the ARGO-YBJ cosmic ray experiment

2009-11-15T23:00:00Z

Proton-air cross section measurement with the ARGO-YBJ cosmic ray experiment Aielli, G.; Bacci, Cesare; Bartoli, B.; Bernardini, P.; Bi, X. J.; Bleve, C.; Branchini, Paolo; Budano, A.; Bussino, Severino; Calabrese Melcarne, A. K.; Camarri, P.; Cao, Z.; Cappa, A.; Cardarelli, R.; Catalanotti, S.; Cattaneo, C.; Celio, Paola; Chen, S. Z.; Chen, Y.; Cheng, N.; Creti, P.; Cui, S. W.; Dai, B. Z.; D'Ali Staiti, G.; Danzengluobu; Dattoli, M.; De Mitri, I.; D'Ettorre Piazzoli, B.; De Vincenzi, Mario; Di Girolamo, T.; Ding, X. H.; Di Sciascio, G.; Feng, C. F.; Feng, Zhaoyang; Feng, Zhenyong; Galeazzi, Fulvio; Galeotti, P.; Gargana, Riccardo; Gou, Q. B.; Guo, Y. Q.; He, H. H.; Hu, Haibing; Hu, Hongbo; Huang, Q.; Iacovacci, M.; Iuppa, R.; James, Irina; Jia, H. Y.; Labaciren; Li, H. J.; Li, J. Y.; Li, X. X.; Liberti, B.; Liguori, G.; Liu, C.; Liu, C. Q.; Liu, M. Y.; Liu, J.; Lu, H.; Ma, X. H.; Mancarella, G.; Mari, Stefano Maria; Marsella, G.; Martello, D.; Mastroianni, Stefano; Meng, X. R.; Montini, Paolo; Ning, C. C.; Pagliaro, A.; Panareo, M.; Perrone, L.; Pistilli, Pio; Qu, X. B.; Rossi, E.; Ruggieri, Federico; Saggese, L.; Salvini, P.; Santonico, R.; Shen, P. R.; Sheng, X. D.; Shi, F.; Stanescu, Cristian; Surdo, A.; Tan, Y. H.; Vallania, P.; Vernetto, S.; Vigorito, C.; Wang, B.; Wang, H.; Wu, C. Y.; Wu, H. R.; Xu, B.; Xue, L.; Yan, Y. X.; Yang, Q. Y.; Yang, X. C.; Yuan, A. F.; Zha, M.; Zhang, H. M.; Zhang, JiLong; Zhang, JianLi; Zhang, L.; Zhang, P.; Zhang, X. Y.; Zhang, Y.; Zhaxisangzhu; Zhou, X. X.; Zhu, F. R.; Zhu, Q. Q.; Zizzi, G. 2009-11-16 Physical Review D 80 092004 The proton-air cross section in the energy range 1-100 TeV has been measured by the ARGO-YBJ cosmic ray experiment. The analysis is based on the primary cosmic ray flux attenuation for different atmospheric depths (i.e. zenith angles) and exploits the detector capabilities of selecting the shower development stage by means of hit multiplicity, density and lateral profile measurements at ground. The effects of shower fluctuations, the contribution of heavier primaries and the uncertainties of the hadronic interaction models, have been taken into account. The results have been used to estimate the total proton-proton cross section at center-of-mass energies between 70 and 500 GeV, where no accelerator data are currently available.

ARGO-YBJ constraints on very high energy emission from GRBs

2009-07-31T22:00:00Z

ARGO-YBJ constraints on very high energy emission from GRBs Aielli, G.; Bacci, Cesare; Bartoli, B.; Bernardini, P.; Bi, X. J.; Bleve, C.; Branchini, Paolo; Budano, Antonio; Bussino, Severino; Calabrese Melcarne, A. K.; Camarri, P.; Cao, Z.; Cappa, A.; Cardarelli, R.; Catalanotti, S.; Cattaneo, C.; Celio, Paola; Chen, S. Z.; Chen, Y.; Cheng, N.; Creti, P.; Cui, S. W.; Dai, B. Z.; D'Ali Staiti, G.; Danzengluobu; Dattoli, M.; De Mitri, I.; D'Ettorre Piazzoli, B.; De Vincenzi, Mario; Di Girolamo, T.; Ding, X. H.; Di Sciascio, G.; Feng, C. F.; Feng, Zhaoyang; Feng, Zhenyong; Galeazzi, Fulvio; Galeotti, P.; Gargana, Riccardo; Gou, Q. B.; Guo, Y. Q.; He, H. H.; Hu, Haibing; Hu, Hongbo; Huang, Q.; Iacovacci, M.; Iuppa, R.; James, Irina; Jia, H. Y.; Labaciren; Li, H. J.; Li, J. Y.; Li, X. X.; Liberti, B.; Liguori, G.; Liu, C.; Liu, C. Q.; Liu, M. Y.; Liu, J.; Lu, H.; Ma, X. H.; Mancarella, G.; Mari, Stefano Maria; Marsella, G.; Martello, D.; Mastroianni, S.; Meng, X. R.; Montini, Paolo; Ning, C. C.; Pagliaro, A.; Panareo, M.; Perrone, L.; Pistilli, Pio; Qu, X. B.; Rossi, E.; Ruggieri, Federico; Saggese, L.; Salvini, P.; Santonico, R.; Shen, P. R.; Sheng, X. D.; Shi, F.; Stanescu, Cristian; Surdo, A.; Tan, Y. H.; Vallania, P.; Vernetto, S.; Vigorito, C.; Wang, B.; Wang, H.; Wu, C. Y.; Wu, H. R.; Xu, B.; Xue, L.; Yan, Y. X.; Yang, Q. Y.; Yang, X. C.; Yuan, A. F.; Zha, M.; Zhang, H. M.; Zhang, JiLong; Zhang, JianLi; Zhang, L.; Zhang, P.; Zhang, X. Y.; Zhang, Y.; Zhaxisangzhu; Zhou, X. X.; Zhu, F. R.; Zhu, Q. Q.; Zizzi, G. 2009-08 Astroparticle Physics 32 47-52 The ARGO-YBJ (Astrophysical Radiation Ground-based Observatory at YangBajing) experiment is designed for very high energy gamma-astronomy and cosmic ray researches. Due to the full coverage of a large area(5600 m(2)) with resistive plate chambers at a very high altitude (4300m a.s.l.), the ARGO-YBJ detector is used to search for transient phenomena, such as Gamma-ray bursts (GRBs). Because the ARGO-YBJ detector has a large field of view (similar to 2 sr) and is operated with a high duty cycle (>90%), it is well suited for GRB surveying and can be operated in searches for high energy GRBs following alarms set by satellite-borne observations at lower energies. In this paper, the sensitivity of the ARGO-YBJ detector for GRB detection is estimated. Upper limits to fluence with 99% confidence level for 26 GRBs inside the field of view from June 2006 to January 2009 are set in the two energy ranges 10-100 GeV and 10 GeV-1 TeV.

Search for gamma ray bursts with the argo-ybj detector in scaler mode

2009-06-30T22:00:00Z

Search for gamma ray bursts with the argo-ybj detector in scaler mode Aielli, G.; Bacci, Cesare; Barone, F.; Bartoli, B.; Bernardini, P.; Bi, X. J.; Bleve, C.; Branchini, P.; Budano, A.; Bussino, S.; Melcarne, A. K. Calabrese; Camarri, P.; Cao, Z.; Cappa, A.; Cardarelli, R.; Catalanotti, S.; Cattaneo, C.; Cavaliere, S.; Celio, Paola; Chen, S. Z.; Cheng, N.; Creti, P.; Cui, S. W.; Dai, B. Z.; Staiti, G. D'Ali; Danzengluobu; Dattoli, M.; De Mitri, I.; De Rosa, R.; Piazzoli, B. D'Ettorre; De Vincenzi, Mario; Di Girolamo, T.; Ding, X. H.; Di Sciascio, G.; Feng, C. F.; Feng, Zhaoyang; Feng, Zhenyong; Galeazzi, F.; Galeotti, P.; Gao, X. Y.; Gargana, R.; Garufi, F.; Gou, Q. B.; Guo, Y. Q.; He, H. H.; Hu, Haibing; Hu, Hongbo; Huang, Q.; Iacovacci, M.; Iuppa, R.; James, Irina; Jia, H. Y.; Labaciren; Li, H. J.; Li, J. Y.; Liberti, B.; Liguori, G.; Liu, C. Q.; Liu, J.; Lu, H.; Mancarella, G.; Mari, Stefano Maria; Marsella, G.; Martello, D.; Mastroianni, S.; Meng, X. R.; Mu, J.; Ning, C. C.; Palummo, L.; Panareo, M.; Perrone, L.; Pistilli, Pio; Qu, X. B.; Rossi, E.; Ruggieri, F.; Saggese, L.; Salvini, P.; Santonico, R.; Segreto, A.; Shen, P. R.; Sheng, X. D.; Shi, F.; Stanescu, C.; Surdo, A.; Tan, Y. H.; Vallania, P.; Vernetto, S.; Vigorito, C.; Wang, H.; Wang, Y. G.; Wu, C. Y.; Wu, H. R.; Xu, B.; Xue, L.; Yang, H. T.; Yang, Q. Y.; Yang, X. C.; Yu, G. C.; Yuan, A. F.; Zha, M.; Zhang, H. M.; Zhang, J. L.; Zhang, L.; Zhang, P.; Zhang, X. Y.; Zhang, Y.; Zhaxisangzhu; Zhou, X. X.; Zhu, F. R.; Zhu, Q. Q.; Zizzi, G. 2009-07 Astrophysical journal 699 1281-1287 We report on the search for gamma ray bursts (GRBs) in the energy range1-100 GeV in coincidence with the prompt emission detected bysatellites using the Astrophysical Radiation with Ground-basedObservatory at YangBaJing (ARGO-YBJ) air shower detector. Thanks to itsmountain location (Yangbajing, Tibet, People's Republic of China, 4300m above sea level), active surface (similar to 6700 m(2) of ResistivePlate Chambers), and large field of view (similar to 2 sr, limited onlyby the atmospheric absorption), the ARGO-YBJ air shower detector isparticularly suitable for the detection of unpredictable and shortduration events such as GRBs. The search is carried out using the"single particle technique," i.e., counting all the particles hittingthe detector without measurement of the energy and arrival direction ofthe primary gamma rays. Between 2004 December 17 and 2009 April 7, 81GRBs detected by satellites occurred within the field of view ofARGO-YBJ (zenith angle theta <= 45 degrees). It was possible to examine62 of these for > 1 GeV counterpart in the ARGO-YBJ data finding nostatistically significant emission. With a lack of detected spectra inthis energy range fluence upper limits are profitable, especially whenthe redshift is known and the correction for the extragalacticabsorption can be considered. The obtained fluence upper limits reachvalues as low as 10(-5) erg cm(-2) in the 1-100 GeV energy region.Besides this individual search for a higher energy counterpart, astatistical study of the stack of all the GRBs both in time and inphase was made, looking for a common feature in the GRB high-energyemission. No significant signal has been detected.

Measurement of sigma(e+ e- -> pi+ pi- gamma) and the di-pion contribution to the muon anomaly with the KLOE detector

2008-12-31T23:00:00Z

Measurement of sigma(e+ e- -> pi+ pi- gamma) and the di-pion contribution to the muon anomaly with the KLOE detector Ambrosino, F.; Antonelli, A.; Antonelli, M.; Archilli, F.; Bacci, Cesare; Beltrame, P.; Bencivenni, G.; Bertolucci, S.; Bini, C.; Bloise, C.; Bocchetta, S.; Bossi, F.; Branchini, P.; Campana, P.; Capon, G.; Capussela, T.; Ceradini, Filippo; Chi, S.; Chiefari, G.; Ciambrone, P.; Crucianelli, F.; De Lucia, E.; De Santis, A.; De Simone, P.; De Zorzi, G.; Denig, A.; Di Domenico, A.; Di Donato, C.; Di Falco, S.; Di Micco, Biagio; Doria, A.; Dreucci, M.; Felici, G.; Ferrari, A.; Ferrer, M. L.; Fiore, S.; Forti, C.; Franzini, P.; Gatti, C.; Gauzzi, P.; Giovannella, S.; Gorini, E.; Graziani, E.; Incagli, M.; Kluge, W.; Kulikov, V.; Lacava, F.; Lanfranchi, G.; Lee-Franzini, J.; Leone, D.; Martemianov, M.; Martini, M.; Massarotti, P.; Mei, W.; Meola, S.; Miscetti, S.; Moulson, M.; Mueller, S.; Murtas, F.; Napolitanoe, M.; Nguyen, Federico; Palutan, M.; Pasqualucci, E.; Passeri, A.; Patera, V.; Perfetto, F.; Primavera, M.; Santangelo, P.; Saracino, G.; Sciascia, B.; Sciubba, A.; Sibidanov, A.; Spadaro, T.; Testa, M.; Tortora, L.; Valente, P.; Valeriani, B.; Venanzoni, G.; Versaci, R.; Xu, G. 2009-01 PHYSICS LETTERS B 670 285-291 We have measured the cross section sigma(e+ e- -> pi+ pi- gamma) at DAFNE, the Frascati phi-factory, using events with initial state radiation photons emitted at small angle andinclusive of final state radiation. We present the analysis of a newdata set corresponding to an integrated luminosity of 240 pb(-1). Wehave achieved a reduced systematic uncertainty with respect topreviously published KLOE results. From the cross section we obtain thepion form factor and the contribution to the muon magnetic anomaly fromtwo-pion states in the mass range 0.592 < M pi pi < 0.975 GeV. For the latter we find Delta(pi pi)_a(mu) = (387.2 +/- 0.5(stat) +/- 2.4(exp)+/- 2.3(th)) x 10^(-10).