Publications (12)18.43 Total impact
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Article: Measurement of proton-proton inelastic scattering cross-section at √s = 7 TeV
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ABSTRACT: The TOTEM experiment at the LHC has measured the inelastic proton-proton cross-section at $\sqrt {s}= 7\,{\mathrm { TeV}}$ in a β* = 90 m run with low inelastic pile-up. The measurement was based on events with at least one charged particle in the T2 telescope acceptance of 5.3 < |η| < 6.5 in pseudorapidity. Combined with data from the T1 telescope, covering 3.1 < |η| < 4.7, the cross-section for inelastic events with at least one |η| ≤ 6.5 final-state particle was determined to be (70.5 ± 2.9) mb. This cross-section includes all central diffractive events of which maximally 0.25 mb is estimated to escape the detection of the telescopes. Based on models for low mass diffraction, the total inelastic cross-section was deduced to be (73.7 ± 3.4) mb. An upper limit of 6.31 mb at 95% confidence level on the cross-section for events with diffractive masses below 3.4 GeV was obtained from the difference between the overall inelastic cross-section obtained by TOTEM using elastic scattering and the cross-section for inelastic events with at least one |η| ≤ 6.5 final-state particle.EPL (Europhysics Letters) 01/2013; 101:21003. · 2.17 Impact Factor -
Article: Luminosity-independent measurements of total, elastic and inelastic cross-sections at √s = 7 TeV
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ABSTRACT: The TOTEM experiment at the LHC has performed the first luminosity-independent determination of the total proton-proton cross-section at √s = 7 TeV . This technique is based on the optical theorem and requires simultaneous measurements of the inelastic rate – accomplished with the forward charged-particle telescopes T1 and T2 in the range 3.1 < |η| < 6.5 – and of the elastic rate by detecting the outcoming protons with Roman Pot detectors. The data presented here were collected in a dedicated run in 2011 with special beam optics (β* = 90 m) and Roman Pots approaching the beam close enough to register elastic events with squared four-momentum transfers |t| as low as 5centerdot10−3 GeV2. The luminosity-independent results for the elastic, inelastic and total cross-sections are σel = (25.1 ± 1.1) mb, σinel = (72.9 ± 1.5) mb and σtot = (98.0 ± 2.5) mb, respectively. At the same time this method yields the integrated luminosity, in agreement with measurements by CMS. TOTEM has also determined the total cross-section in two complementary ways, both using the CMS luminosity measurement as an input. The first method sums the elastic and inelastic cross-sections and thus does not depend on the ρ parameter. The second applies the optical theorem to the elastic-scattering measurements only and therefore is free of the T1 and T2 measurement uncertainties. The methods, having very different systematic dependences, give results in excellent agreement. Moreover, the ρ-independent measurement makes a first estimate for the ρ parameter at √s = 7 TeV possible: |ρ| = 0.145 ± 0.091.EPL (Europhysics Letters) 01/2013; 101. · 2.17 Impact Factor -
Article: Measurement of proton-proton inelastic scattering cross-section at √s = 7 TeV
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ABSTRACT: The TOTEM experiment at the LHC has measured the inelastic proton-proton cross-section at √s = 7 TeV in a β* = 90 m run with low inelastic pile-up. The measurement was based on events with at least one charged particle in the T2 telescope acceptance of 5.3 < |η| < 6.5 in pseudorapidity. Combined with data from the T1 telescope, covering 3.1 < |η| < 4.7, the cross-section for inelastic events with at least one |η| ≤ 6.5 final-state particle was determined to be (70.5 ± 2.9) mb. This cross-section includes all central diffractive events of which maximally 0.25 mb is estimated to escape the detection of the telescopes. Based on models for low mass diffraction, the total inelastic cross-section was deduced to be (73.7 ± 3.4) mb. An upper limit of 6.31 mb at 95% confidence level on the cross-section for events with diffractive masses below 3.4 GeV was obtained from the difference between the overall inelastic cross-section obtained by TOTEM using elastic scattering and the cross-section for inelastic events with at least one |η| ≤ 6.5 final-state particle.EPL (Europhysics Letters) 01/2013; 101. · 2.17 Impact Factor -
Article: Measurement of the forward charged particle pseudorapidity density in ppcollisions at √s = 7 TeV with the TOTEM experiment
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ABSTRACT: The TOTEM experiment has measured the charged particle pseudorapidity density dN_{ch}/deta in pp collisions at √s = 7 TeV for 5.3<|eta|<6.4 in events with at least one charged particle with transverse momentum above 40 MeV/c in this pseudorapidity range. This extends the analogous measurement performed by the other LHC experiments to the previously unexplored forward eta region. The measurement refers to more than 99% of non-diffractive processes and to single and double diffractive processes with diffractive masses above ~3.4 GeV/c^2, corresponding to about 95% of the total inelastic cross-section. The dN_{ch}/deta has been found to decrease with |eta|, from 3.84 pm 0.01(stat) pm 0.37(syst) at |eta| = 5.375 to 2.38 pm 0.01(stat) pm 0.21(syst) at |eta| = 6.375. Several MC generators have been compared to data; none of them has been found to fully describe the measurement.EPL (Europhysics Letters) 05/2012; 98. · 2.17 Impact Factor -
Article: Elastic Scattering and Total Cross-Section in p+p reactions measured bythe LHC Experiment TOTEM at √s = 7 TeV
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ABSTRACT: Proton-proton elastic scattering has been measured by the TOTEM experiment at the CERN Large Hadron Collider at sqrt{s} = 7 TeV in special runs with the Roman Pot detectors placed as close to the outgoing beam as seven times the transverse beam size. The differential cross-section measurements are reported in the |t|-range of 0.36 to 2.5 GeV^2. Extending the range of data to low t values from 0.02 to 0.33 GeV^2,and utilizing the luminosity measurements of CMS, the total proton-proton cross section at sqrt(s) = 7 TeV is measured to be (98.3 +- 0.2(stat) +- 2.8(syst)) mb.Progress of Theoretical Physics Supplement 04/2012; 193. · 1.06 Impact Factor -
Article: Proton-proton elastic scattering at the LHC energy of √s = 7 TeV
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ABSTRACT: Proton-proton elastic scattering has been measured by the TOTEM experiment at the CERN Large Hadron Collider at {\surd}s = 7 TeV in dedicated runs with the Roman Pot detectors placed as close as seven times the transverse beam size (sbeam) from the outgoing beams. After careful study of the accelerator optics and the detector alignment, |t|, the square of four-momentum transferred in the elastic scattering process, has been determined with an uncertainty of d t = 0.1GeV p|t|. In this letter, first results of the differential cross section are presented covering a |t|-range from 0.36 to 2.5GeV2. The differential cross-section in the range 0.36 < |t| < 0.47 GeV2 is described by an exponential with a slope parameter B = (23.6{\pm}0.5stat {\pm}0.4syst)GeV-2, followed by a significant diffractive minimum at |t| = (0.53{\pm}0.01stat{\pm}0.01syst)GeV2. For |t|-values larger than ~ 1.5GeV2, the cross-section exhibits a power law behaviour with an exponent of -7.8_\pm} 0.3stat{\pm}0.1syst. When compared to predictions based on the different available models, the data show a strong discriminative power despite the small t-range covered.EPL (Europhysics Letters) 10/2011; 95. · 2.17 Impact Factor -
Article: First measurement of the total proton-proton cross section at the LHCenergy of √s =7 TeV
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ABSTRACT: TOTEM has measured the differential cross-section for elastic proton-proton scattering at the LHC energy of \sqrt{s} = 7\,{\rm TeV} analysing data from a short run with dedicated large-β* optics. A single exponential fit with a slope B=(20.1±0.2stat±0.3syst) GeV−2 describes the range of the four-momentum transfer squared |t| from 0.02 to 0.33 GeV2. After the extrapolation to |t|=0, a total elastic scattering cross-section of (24.8±0.2stat±1.2syst) mb was obtained. Applying the optical theorem and using the luminosity measurement from CMS, a total proton-proton cross-section of (98.3±0.2stat±2.8syst) mb was deduced which is in good agreement with the expectation from the overall fit of previously measured data over a large range of center-of-mass energies. From the total and elastic pp cross-section measurements, an inelastic pp cross-section of (73.5\pm 0.6^{{\rm stat}}{}{\fontsize{6}{6}\selectfont{\begin{array}{c}{+1.8}\\{-1.3}\end{array}}}\,{}^{{\rm syst}})\,{\rm mb} was inferred.EPL (Europhysics Letters) 10/2011; 96. · 2.17 Impact Factor -
Article: Proton-proton elastic scattering at the LHC energy of$backslash$ chem $$$backslash$ sqrt $$s$$= 7$backslash$, TeV$$
EPL (Europhysics Letters) 01/2011; 95(4):41001. · 2.17 Impact Factor -
Article: Proton-proton elastic scattering at the LHC energy of$backslash$ chem $$$backslash$ sqrt $$s$$= 7$backslash$, TeV$$
EPL (Europhysics Letters) 01/2011; 95:41001. · 2.17 Impact Factor -
Conference Proceeding: Offline Software for the TOTEM Experiment at the LHC
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ABSTRACT: The TOTEM Experiment will measure the total pp cross-section with the luminosity-independent method and study elastic and diffractive scattering at the LHC. This article gives a general description of the TOTEM Offline system and focuses on its specific software components.ASTROPARTICLE, PARTICLE AND SPACE PHYSICS, DETECTORS AND MEDICAL PHYSICS APPLICATIONS, in Villa Olmo, Como, Italy; 01/2010 -
Article: The TOTEM electronics system
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ABSTRACT: TOTEM is an LHC experiment around the same interaction point as CMS. It contains cathode strip chambers (CSC) and gas electron multiplier detectors (GEM) in the CMS cavern and 24 Roman Pots with silicon strip detectors in the LHC tunnel. TOTEM should run both standalone and together with CMS, and should be fully compatible with CMS. All three sub-detectors provide level one trigger building signals and use the same chips: VFAT2 providing both tracking data and fast trigger generation signals, the programmable Coincidence Chip, and the LVDS repeater chip. The same counting room hardware receives and handles both trigger building and tracking data.Topical Workshop on Electronics for Particle Physics. 01/2007; -
Article: Diffraction and Total Cross-Section at the Tevatron and the LHC
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ABSTRACT: At the Tevatron, the total p_bar-p cross-section has been measured by CDF at 546 GeV and 1.8 TeV, and by E710/E811 at 1.8 TeV. The two results at 1.8 TeV disagree by 2.6 standard deviations, introducing big uncertainties into extrapolations to higher energies. At the LHC, the TOTEM collaboration is preparing to resolve the ambiguity by measuring the total p-p cross-section with a precision of about 1 %. Like at the Tevatron experiments, the luminosity-independent method based on the Optical Theorem will be used. The Tevatron experiments have also performed a vast range of studies about soft and hard diffractive events, partly with antiproton tagging by Roman Pots, partly with rapidity gap tagging. At the LHC, the combined CMS/TOTEM experiments will carry out their diffractive programme with an unprecedented rapidity coverage and Roman Pot spectrometers on both sides of the interaction point. The physics menu comprises detailed studies of soft diffractive differential cross-sections, diffractive structure functions, rapidity gap survival and exclusive central production by Double Pomeron Exchange.Deile , M , Aurola , A , Brücken , E , Heino , J , Hilden , T , Kalliopuska , J , Kurvinen , K , Lauhakangas , R , Lämsä , J , Oljemark , F , Ojala , J , Orava , R , Österberg , K , Saarikko , H & TOTEM Collaboration 2006 , ' Diffraction and Total Cross-Section at the Tevatron and the LHC ' , pp. 40-45 .
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Institutions
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2011
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University of Helsinki
Helsinki, Province of Southern Finland, Finland
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