Physics potential and experimental challenges of the LHC luminosity upgrade

We discuss the physics potential and the experimental challenges of an upgraded LHC running at an instantaneous luminosity of 10³⁵ cm^-2s^-1. The detector R&D needed to operate ATLAS and CMS in a very high radiation environment and the expected detector performance are discussed. A few examples of the increased physics potential are given, ranging from precise measurements within the Standard Model (in particular in the Higgs sector) to the discovery reach for several New Physics processes. Received: 25 November 2003, Revised: 21 October 2004, Published online: 18 January 2005 Conveners: F. Gianotti, M.L. Mangano, T. Virdee Contributors: S. Abdullin, G. Azuelos, A. Ball, D. Barberis, A. Belyaev, P. Bloch, M. Bosman, L. Casagrande, D. Cavalli, P. Chumney, S. Cittolin, S.Dasu, A. De Roeck, N. Ellis, P. Farthouat, D. Fournier, J.-B. Hansen, I. Hinchliffe, M. Hohlfeld, M. Huhtinen, K. Jakobs, C. Joram, F. Mazzucato, G.Mikenberg, A. Miagkov, M. Moretti, S. Moretti, T. Niinikoski, A. Nikitenko, A. Nisati, F. Paige, S. Palestini, C.G. Papadopoulos, F. Piccinini, R. Pittau, G. Polesello, E. Richter-Was, P. Sharp, S.R. Slabospitsky, W.H. Smith, S. Stapnes, G. Tonelli, E. Tsesmelis, Z. Usubov, L. Vacavant, J. van der Bij, A. Watson, M. Wielers A. Nikitenko: On leave of absence from ITEP, Moscow, Russia. F. Piccinini: On leave of absence from INFN, Sezione di Pavia, Italy.     

Electromagnetic moments of the 7+ rotational bandhead in116Sb

The lifetimes of low-lying negative parity yrast levels have been measured in¹³¹La using the recoil distance Doppler shift method. The nuclear reaction employed was¹¹⁶Cd+¹⁹F at a beam energy of 80 MeV. The data were analysed using the differential decay curve method. The E2 transition strengths for negative parity yrast states and the energy spectra are well described by coupling a fermion to a-soft core in the frame of the interacting boson fermion approximation model.We gratefully acknowledge discussions with R.F. Casten. One of us (N.V.Z.) is grateful to Universität zu Köln for its hospitality. This work was supported by the Bundesministerium für Forschung und Technology — Germany under contract 06OK143 and by Institute of Atomic Physics — Romania under contract 62-91-1.     

Rotation-like behavior as a function of projectile energy and target mass

The azimuthal distributions produced in the intermediate energy⁴⁰Ar-induced reactions are calculated via the nuclear transport theory. The rotational collective motion is observed from the mid-rapidity particles emission. In addition to the investigation on particle emission in the coordinate space, the momentum distributions of emitted particles as a function of azimuthal angle are also discussed. The azimuthal distributions are fitted by performing Legendre polynomial expansion to second order. By incorporating the fluctuation between the estimated and true reaction plane into our calculations, quantitative agreements with the data are obtained for⁴⁰Ar+²⁷Al reactions below 85 MeV/nucleon. It is found that the rotation-like behavior becomes stronger with the increasing of the impact parameter and weaker with the increasing of the projectile energy. For⁴⁰Ar+²⁷Al system at about 85 MeV/nucleon the rotation-like behavior almost vanishes and the mid-rapidity azimuthal distribution tends to be isotropic. For 35 MeV/nucleon⁴⁰Ar-induced reactions the rotation-like behavior becomes weaker and the out-of-plane enhancement of particle emission appears with the increasing of target mass. The possible origins of these target mass dependent azimuthal distributions at mid-rapidity are discussed.     

Nuclear and electromagnetic fragmentation of 2.25-TeV197Au nuclei

We report the first measurement of the total charge-loss cross section _tot=_em+_nuc and partial cross sections (for Z=1, 2, ..., 9) of 11.4 A GeV¹⁹⁷Au nuclei in various targets. The large Coulomb barrier for Au reduces the electromagnetic contribution _em in a Pb target to only 18% of _nuc, compared with 70% for 14.5 A GeV²⁸Si and 120% for 200 A GeV³²S. With _em taken to be Z _T ^1.8 , _nuc can be fitted with _nuc=(A _P ^1/3 +A _T ^1/3 –b)², with b=0.83 and =59 mb, essentially the same as found at energies of 1 to 2 A GeV. Electromagnetic partial cross sections for Z=1 exceed 40 mb in the Pb, Sn, Cu, and Fe targets and are substantial for larger values ofZ in the heavier targets.We are indebted to D. Beavis and the staff of the Alternating Gradient Synchrotron at Brookhaven National Laboratory for producing the beam of 11.4 A GeV Au ions, to D. Snowden-Ifft for his efforts in developing the automated scanning system, and to S. Hirzebruch for a useful discussion. This work was supported in part by the Office of Energy Research, Office of High Energy and Nuclear Physics, Division of High Energy Physics, of the Department of Energy under contract No. DEAC03-76SF00098.     

Measurement of the e+e? → π+π? cross section with the CMD-2 detector in the 370–520-MeV energy range

The results of the experiment on the measurement of the e ⁺ e ⁻ → π⁺π⁻ cross section in a cm energy range of 370–520 MeV are presented. The systematic measurement error is equal to 0.7%. In the vector dominance model, the pion electromagnetic radius is calculated using all the CMD-2 data on the pion form factor. The cross section for the production of a muon pair is measured in the energy range of the experiment. Original Russian Text ? V.M. Aul’chenko, R.R. Akhmetshin, V.Sh. Banzarov, L.M. Barkov, N.S. Bashtovoĭ, D.V. Bondarev, A.E. Bondar’, A.V. Bragin, N.I. Gabyshev, D.A. Gorbachev, A.A. Grebenyuk, D.N. Grigor’ev, S.K. Dhawan, D.A. Epifanov, A.S. Zaĭtsev, S.G. Zverev, F.V. Ignatov, V.F. Kazanin, S.V. Karpov, I.A. Koop, P.P. Krokovny, A.S. Kuz’min, I.B. Logashenko, P.A. Lukin, A.P. Lysenko, A.I. Mil’shteĭn, K.Yu. Mikhaĭlov, I.N. Nesterenko, M.A. Nikulin, A.V. Otboev, V.S. Okhapkin, E.A. Perevedentsev, A.S. Popov, S.I. Redin, B.L. Roberts, N.I. Root, A.A. Ruban, N.M. Ryskulov, A.L. Sibidanov, V.A. Sidorov, A.N. Skrinsky, V.P. Smakhtin, I.G. Snopkov, E.P. Solodov, J.A. Thompson, G.V. Fedotovich, B.I. Khazin, V.W. Hughes, A.G. Shamov, Yu.M. Shatunov, B.A. Shvarts, S.I. éĭdel’man, Yu.V. Yudin, 2006, published in Pis’ma v Zhurnal éksperimental’noĭ i Teoreticheskoĭ Fiziki, 2006, Vol. 84, No. 8, pp. 491–495.     

Baikal neutrino telescope: Status, results, and prospects of development

The main physical results obtained with the Baikal neutrino telescope NT200 during the period 1998–2003 are reviewed: the limits for the diffuse flux of high-energy neutrinos, high-energy muons, and magnetic monopoles and the results of search for neutrinos from the center of the Earth due to annihilation of weakly interacting massive particles and from local neutrino sources. In April, 2005, the neutrino telescope NT200 was extended by introduction of three new strings, located at a distance of 100 m from the NT200 center. The new deep-water complex NT200+ has an effective volume for detecting cascades from high-energy neutrinos larger than that of NT200 by a factor of 4. At a cascade energy of 10 PeV, the effective volume of the new complex is 10⁷ m³. Further development of the Baikal neutrino experiment is related to the design and fabrication of a detector with a volume of about 1 km³. Original Russian Text ? K.V.Antipin, V.M. Ainutdinov, V.A. Balkanov, I.A. Belolaptikov, D.A. Borshchev, N.M. Budnev, R.V. Vasil’ev, R. Vishnevskii, I.A. Danil’chenko, G.V. Domogatskii, A.A. Doroshenko, A.P. D’yachok, Zh.-A.M. Dzhilkibaev, O.N. Gaponenko, K.V. Golubkov, O.A. Gress, T.I. Gress, O.I. Grishin, V.A. Zhukov, A.M. Klabukov, A.I. Klimov, A.A. Kochanov, K.V. Konishchev, A.P. Koshechkin, L.A. Kuz’michev, V.F. Kulepov, E. Middel, T. Mikokaiskii, M.B. Milenin, R.R. Mirgazov, S.P. Mikheev, E.A. Osipova, G.L. Pan’kov, L.V. Pan’kov, A.I. Panfilov, D.P. Petukhov, E.N. Pliskovskii, P.G. Pokhil, V.A. Poleshchuk, E.G. Popova, V.V. Prosin, M.I. Rozanov, V.Yu. Rubtsov, Yu.A. Semenei, B.A. Tarashchanskii, S.V. Fialkovskii, B.K. Shaibonov, A.A. Sheifler, A.V. Shirokov, K. Spiring, I.V. Yashin, 2007, published in Izvestiya Rossiiskoi Akademii Nauk. Seriya Fizicheskaya, 2007, Vol. 71, No. 4, pp. 597–601.     

Physics beyond Standard Model: Working group 3 report

This is a summary of the beyond the Standard Model (including model building) working group of the WHEPP-X workshop held at Chennai from January 3 to 15, 2008. Participants: Neelima Agarwal, S K Agarwalla, C S Aulakh, A Belyaev, S S Biswal, B Bhattacharjee, G Bhattacharyya, L Calibbi, D Choudhury, E J Chun, D Das, A De Roeck, N G Deshpande, E Dudas, A Giri, D Grellshceid, R Godbole, S Goswami, M Guchait, M Hirsch, R Kaul, B Kodrani, M C Kumar, A Kundu, Y Mambrini, P Mathews, B Mellado, R Mohanta, S Mohanty, A Nyffeler, S Pakvasa, M K Parida, M Passera, C Petridou, S Poddar, P Poulose, A Rajaraman, G Rajasekaran, V Ravindran, Kumar Rao, D P Roy, Probir Roy, K A Saheb, V H Satheeshkumar, T Schwetz, A Tripathi, R Vaidya and S Vempati     

Angular Distributions for

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Pair-Breaking Critical Current Density of Two-Band Superconductor MgB2

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Momentum distributions of projectile fragments produced in the cold and hot fragmentation of relativistic136Xe and197Au projectiles

The longitudinal-momentum distributions of projectile fragments from 0.8 A GeV¹³⁶Xe and 1 A GeV¹⁹⁷Au projectiles impinging on targets of beryllium and aluminium, respectively, have been measured using the projectile-fragment separator FRS at GSI. Different momentum distributions have been found for two different classes of fragmentation processes: the abundant hot fragmentation with several nucleons evaporated from the prefragments, and the rare cold fragmentation with only protons removed from the projectile, but no nucleons evaporated. The data are compared to model calculations.This article comprises part of the Ph.D. thesis of B. Voss     

Laser-induced free-carrier absorption in Si single crystal

The transmitted energy density in thin single Si crystal, wafers is measured at=1.06 m as a function of the incident energy density for a Nd laser pulse of 30 ns duration. Non-linear effects begin to become important at about 0.3 J/cm². The contribution due to free-carriers is separated from the interband one by using measurements made at low energy density and at different sample temperatures in the 20°–150 °C range. The time dependence of the free-carrier concentration and of the lattice temperature is computed for different values of the Auger constant. The experimental data in the 0.2–2.5 J/cm² energy density range are fitted with an Auger constant of 10^–30 cm⁶s^–1.Work supported in part by M.P.I. and G.N.S.M.-C.N.R.     

SINGAO: a very large telescope for neutrino gamma astronomy and cosmic-ray studies

Summary We discuss the feasibility of a telescope consisting in a sampling array for extensive air showers measure combined with a muon tracking device. The sampling array will extend over a surface of ≥10⁷ m² while the muon tracking device will cover ≥10⁴ m². The telescope should be done with resistive plates counters and would become a very powerful device to study high-energy neutrinos and gamma-ray astronomy as well as cosmicray physics up to the highest energy (≥10¹⁹ eV) region. The content of this paper has been elaborated with the following people interested in performing the experiment: M. De Palma, G. Iaselli, C. Maggi, S. Natali, S. Nuzzo, A. Ranieri, C. Raso, F. Romano, F. Ruggeri, G. Selvaggi, P. Tempesta, G. Zito; A. Rossi, G. Susinno; A. Grillo, F. Ronga, V. Valente; P. Bernardini, P. Pistilli; A. Watson, R. Reid, M. Lawrence; M. Ambrosio, G. Barbarino, B. Bartoli, V. Silvestrini; R. Buccheri, M. Carollo, O. Catalano, J. Linsley, L. Scarsi; G. Bressi, A. Lanza, M. Cambiaghi, S. Ratti; M. Bonori, G. D'Agostini; M. De Vincenzi, E. Lamanna, P. Lipari, G. Martellotti, F. Massa, M. Mattioli, A. Nigro, S. Petrera; R. Cardarelli, F. Rossi, R. Santonico; L. De Cesare, G. Grella, M. Guida, F. Mancini, G. Marini, G. Romano, G. Vitiello; C. Cappa, B. D'Ettore Piazzoli, P. Ghia, G. Gomez, P. Trivero. [Bari, Cosenza, Laboratori Nazionali di Frascati Lecce, Leeds, Napoli, Palermo, Pavia, Roma I, Roma II, Salerno, Torino, Istituto di Cosmogeofisica del CNR].     

Studying of hypernuclei with nuclotron beams

A spectrometer is created to study relativistic hypernuclei produced with beams of accelerated nuclei from the Nuclotron facility (Dubna, JINR). Test runs have been carried out and the conclusion is drawn that the properties of the facility meet the requirements of the task of searching for unknown and studying poorly known neutron-rich hypernuclei. Original Russian Text ? A.V. Averyanov, S.A. Avramenko, V.D. Aksinenko, M.Kh. Anikina, S.N. Bazylev, V.P. Balandin, Yu.A. Batusov, Yu.A. Belikov, Yu.T. Borzunov, O.V. Borodina, A.I. Golokhvastov, L.B. Golovanov, C. Granja, A.B. Ivanov, Yu.L. Ivanov, A.Yu. Isupov, Z. Kohout, A.M. Korotkova, A.G. Litvinenko, J. Lukstiņš, A.I. Malakhov, L. Majling, O. Majlingova, P.K. Manyakov, V.T. Matyushin, I.I. Migulina, G.P. Nikolaevsky, O.B. Okhrimenko, A.N. Parfenov, N.G. Parfenova, V.F. Peresedov, S.N. Plyashkevich, S. Pospišil, P.A. Rukoyatkin, I.S. Saitov, R.A. Salmin, V.M. Slepnev, I.V. Slepnev, M. Solar, B. Sopko, V. Sopko, E.A. Strokovsky, V.V. Tereshchenko, A.A. Feshchenko, T. Horazdovsky, D. Chren, Yu.A. Chencov, I.P. Yudin, 2008, published in Yadernaya Fizika, 2008, Vol. 71, No. 12, pp. 2137–2145.     

Correlations between emerging alpha-particles and heavy ions in 32S+197 Au collisions

In-plane angular correlations between α-particles and projectile residue nuclei (Z=5?22) emerging from ³²S+¹⁹⁷Au collisions have been measured at 373 MeV incident energy. In the combined Coulomb field of the projectile residue and the target nucleus coincident α-particles are strongly focused into a narrow cone. Model calculations indicate that α-emission originates from the region of the projectile which is facing the target nucleus during the collision.     

Production of helium fragments in197Au-emulsion collisions at 10.6 A GeV

We present a systematic analysis on the helium projectile fragments produced from 10.6 A GeV¹⁹⁷Auemulsion interactions in an experiment conducted at the Brookhaven AGS. Total charge changing and partial production cross-sections are measured experimentally on the basis of helium multiplicity. The multiplicity distribution of helium fragments which are produced collectively obey a KNO scaling. The transverse momentum distribution of these particles indicates that they are produced from two different independent sources.We are thankful to the BNL technical staff and specially to Dr. D. Beavis for his help in the exposure of emulsion stacks. Thanks are due to Profs. Y. Takahashi and G. Romano for their help in the preparation and development of the emulsion stacks. We appreciate the discussions with Prof. H. Stocker and J. Aichelin. This work was supported by D.O.E. under Grant No. DE-FGO2-90ER 40566.     

Single-oscillator model and determination of optical constants of spray pyrolyzed amorphous SnO<Subscript>2</Subscript> thin films

It has recently been shown that growth of a multilayer structure with one or more delta-layers at high temperature leads to spreading and asymmetrization of the dopant distribution [see, for example, E.F.J. Schubert, Vac. Sci. Technol. A. 8, 2980 (1990), A.M. Nazmul, S. Sugahara, M. Tanaka, J. Crystal Growth 251, 303 (2003); R.C. Newman, M.J. Ashwin, M.R. Fahy, L. Hart, S.N. Holmes, C. Roberts, X. Zhang, Phys. Rev. B 54, 8769 (1996); E.F. Schubert, J.M. Kuo, R.F. Kopf, H.S. Luftman, L.C. Hopkins, N.J. Sauer, J. Appl. Phys. 67, 1969 (1990); P.M. Zagwijn, J.F. van der Veen, E. Vlieg, A.H. Reader, D.J. Gravesteijn, J. Appl. Phys. 78, 4933 (1995); W.S. Hobson, S.J. Pearton, E.F. Schubert, G. Cabaniss, Appl. Phys. Lett. 55, 1546 (1989); Delta Doping of Semiconductors, edited by E.F. Schubert (Cambridge University Press, Cambridge, 1996); Yu.N. Drozdov, N.B. Baidus', B.N. Zvonkov, M.N. Drozdov, O.I. Khrykin, V.I. Shashkin, Semiconductors 37, 194 (2003); E. Skuras, A.R. Long, B. Vogele, M.C. Holland, C.R. Stanley, E.A. Johnson, M. van der Burgt, H. Yaguchi, J. Singleton, Phys. Rev. B 59, 10712 (1999); G. Li, C. Jagadish, Solid-State Electronics 41, 1207 (1997)]. In this work analytical and numerical analysis of dopant dynamics in a delta-doped area of a multilayer structure has been accomplished using Fick's second law. Some reasons for asymmetrization of a delta-dopant distribution are illustrated. The spreading of a delta-layer has been estimated using example materials of a multilayer structure, a delta-layer and an overlayer.     

Shape Coexistence for 179Hg in Relativistic Mean-Field Theory

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A first look at Au+Au collisions at RHIC energies using the PHOBOS detector

The PHOBOS detector has been used to study Au + Au collisions at√^sNN = 56,130, and 200 GeV Several global observables have been measured and the results are compared with theoretical models. These observables include the charged-particle multiplicity measured as a function of beam energy, pseudo-rapidity, and centrality of the collision. A unique feature of the PHOBOS detector is its almost complete angular coverage such that these quantities can be studied over a pseudo-rapidity interval of |η|≤5.4. This allows for an almost complete integration of the total charged particle yield, which is found to be about N _ch ^tot = 4200 ±470 at √^sNN = 130 GeV and N _ch ^tot = 5300 ±530 at √^sNN = 200 GeV. The ratio of anti-particles to particles emitted in the mid-rapidity region has also been measured using the PHOBOS magnetic spectrometer. Of particular interest is the ratio of anti-protons to protons in the mid-rapidity region, which was found to be (i.e.921-1) at √^sNN = 130 GeV. This high value suggests that an almost baryon-free region has been produced in the collisions.     

Re-study of Nucleon Pole Contribution in J/

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Complete and incomplete fusion in12C+93Nb and16O+89Y reactions

Excitation functions for the evaporation residues for the reactions¹²C+⁹³Nb and¹⁶O+⁸⁹Y in the projectile energy range of 4 to 6.5 MeV/amu have been measured using off-line gamma spectrometry. The excitation functions for neutron(xn), proton(pxn) and one alpha(xn) emission channels are practically similar for both the reactions. However the products formed by two alpha(2xn) emission show much higher cross sections in the¹²C+⁹³Nb than the¹⁶O+⁸⁹Y system. This has been explained in terms of the incomplete fusion process involving transfer of an alpha particle from the projectile to the target in the former case.Authors thank Shri D.C. Ephraim for making the rolled metal foils and the operation crew of PELLETRON facility for their help in carrying out the irradiations. Authors are grateful to Dr. P.R. Natarajan, Head Radiochemistry Division for his keen interest in this work.