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Author |
LHCf Collaboration (Adriani, O. et al); Faus-Golfe, A.; Velasco, J. |
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Title |
Measurement of zero degree single photon energy spectra for sqrt(s) = 7 TeV proton-proton collisions at LHC |
Type |
Journal Article |
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Year |
2011 |
Publication |
Physics Letters B |
Abbreviated Journal |
Phys. Lett. B |
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Volume |
703 |
Issue |
2 |
Pages |
128-134 |
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Keywords |
LHC; Ultra-high energy cosmic-ray; Hadron interaction models |
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Abstract |
In early 2010. the Large Hadron Collider forward (LHCf) experiment measured very forward neutral particle spectra in LHC proton-proton collisions. From a limited data set taken under the best beam conditions (low beam-gas background and low occurrence of pile-up events), the single photon spectra at root s = 7 TeV and pseudo-rapidity (eta) ranges from 8.81 to 8.99 and from 10.94 to infinity were obtained for the first time and are reported in this Letter. The spectra from two independent LHCf detectors are consistent with one another and serve as a cross check of the data. The photon spectra are also compared with the predictions of several hadron interaction models that are used extensively for modeling ultra-high energy cosmic-ray showers. Despite conservative estimates for the systematic errors, none of the models agree perfectly with the measurements. A notable difference is found between the data and the DPMJET 3.04 and PYTHIA 8.145 hadron interaction models above 2 TeV where the models predict higher photon yield than the data. The QGSJET II-03 model predicts overall lower photon yield than the data, especially above 2 TeV in the rapidity range 8.81 < eta < 8.99. |
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Address |
[Fukatsu, K; Itow, Y; Kawade, K; Mase, T; Masuda, K; Matsubara, Y; Mitsuka, G; Muraki, Y; Sako, T; Suzuki, K; Taki, K] Nagoya Univ, Solar Terr Environm Lab, Nagoya, Aichi 4648601, Japan, Email: sako@stelab.nagoya-u.ac.jp |
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Thesis |
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Publisher |
Elsevier Science Bv |
Place of Publication |
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Language |
English |
Summary Language |
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Original Title |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0370-2693 |
ISBN |
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Area |
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Expedition |
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Conference |
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Notes |
WOS:000295105500005 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ elepoucu @ |
Serial |
769 |
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Permanent link to this record |
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Author |
ATLAS Collaboration (Aad, G. et al); Amoros, G.; Cabrera Urban, S.; Castillo Gimenez, V.; Costa, M.J.; Escobar, C.; Ferrer, A.; Fiorini, L.; Fuster, J.; Garcia, C.; Gonzalez de la Hoz, S.; Hernandez Jimenez, Y.; Higon-Rodriguez, E.; Irles Quiles, A.; Kaci, M.; Lacasta, C.; Lacuesta, V.R.; Marti-Garcia, S.; Miñano, M.; Mitsou, V.A.; Moles-Valls, R.; Moreno Llacer, M.; Oliver Garcia, E.; Perez Garcia-Estañ, M.T.; Ros, E.; Salt, J.; Solans, C.A.; Soldevila, U.; Sanchez, J.; Torro Pastor, E.; Valladolid Gallego, E.; Valls Ferrer, J.A.; Villaplana Perez, M.; Vos, M.; Wildauer, A. |
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Title |
Measurement of W gamma and Z gamma production in proton-proton collisions at sqrt(s)=7 TeV with the ATLAS detector |
Type |
Journal Article |
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Year |
2011 |
Publication |
Journal of High Energy Physics |
Abbreviated Journal |
J. High Energy Phys. |
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Volume |
09 |
Issue |
9 |
Pages |
072 - 42pp |
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Keywords |
Hadron-Hadron Scattering |
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Abstract |
We present studies of W and Z bosons with associated high energy photons produced in pp collisions at sqrt(s) = 7 TeV. The analysis uses 35 pb(-1) of data collected by the ATLAS experiment in 2010. The event selection requires W and Z bosons decaying into high pT leptons (electrons or muons) and a photon with E(T) > 15 GeV separated from the lepton(s) by a distance Delta R(l, gamma) > 0.7 in eta-phi space. A total of 95 (97) pp -> e(+/-)nu gamma + X (pp -> mu(+/-)nu gamma + X) and 25 (23) pp -> e(+)e(-)gamma + X (pp -> mu(+)mu(-)gamma + X) event candidates are selected. The kinematic distributions of the leptons and photons and the production cross sections are measured. The data are found to agree with Standard Model predictions that include next-to-leading-order O(alpha alpha(s)) contributions. |
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Address |
[Aad, G; Ahles, F; Beckingham, M; Bernhard, R; Bitenc, U; Bruneliere, R; Caron, S; Christov, A; Consorti, V; Ff, AD; Eckert, S; Fehling-Kaschek, M; Flechl, M; Glatzer, J; Hartert, J; Heldmann, M; Herten, G; Horner, S; Jakobs, K; Ketterer, C; Kollefrath, M; Kononov, AI; Kuehn, S; Lai, S; Landgraf, U; Lohwasser, K; Ludwig, I; Ludwig, J; Lumb, D; Mahboubi, K; Meinhardt, J; Mohr, W; Nilsen, H; Parzefall, U; Bueso, XP; Rammensee, M; Runge, K; Rurikova, Z; Schmidt, E; Schumacher, M; Siegert, F; Stoerig, K; Sundermann, JE; Temming, KK; Thoma, S; Tobias, J; Tsiskaridze, V; Venturi, M; Vivarelli, I; von Radziewski, H; Warsinsky, M; Weiser, C; Werner, M; Wiik, LAM; Winkelmann, S; Xie, S; Zimmermann, S] Univ Freiburg, Fak Math & Phys, Freiburg, Germany |
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Thesis |
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Publisher |
Springer |
Place of Publication |
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Editor |
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Language |
English |
Summary Language |
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Original Title |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
1126-6708 |
ISBN |
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Medium |
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Area |
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Expedition |
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Conference |
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Notes |
WOS:000296087000001 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ elepoucu @ |
Serial |
824 |
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Permanent link to this record |
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Author |
ATLAS Collaboration (Aad, G. et al); Amoros, G.; Cabrera Urban, S.; Castillo Gimenez, V.; Costa, M.J.; Escobar, C.; Ferrer, A.; Fiorini, L.; Fuster, J.; Garcia, C.; Gonzalez de la Hoz, S.; Hernandez Jimenez, Y.; Higon-Rodriguez, E.; Irles Quiles, A.; Kaci, M.; Lacasta, C.; Lacuesta, V.R.; Marti-Garcia, S.; Miñano, M.; Mitsou, V.A.; Moles-Valls, R.; Moreno Llacer, M.; Oliver Garcia, E.; Perez Garcia-Estañ, M.T.; Ros, E.; Salt, J.; Solans, C.A.; Soldevila, U.; Sanchez, J.; Torro Pastor, E.; Valladolid Gallego, E.; Valls Ferrer, J.A.; Villaplana Perez, M.; Vos, M.; Wildauer, A. |
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Title |
Measurement of dijet production with a veto on additional central jet activity in pp collisions at sqrt(s)=7 TeV using the ATLAS detector |
Type |
Journal Article |
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Year |
2011 |
Publication |
Journal of High Energy Physics |
Abbreviated Journal |
J. High Energy Phys. |
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Volume |
09 |
Issue |
9 |
Pages |
053 - 36pp |
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Keywords |
Hadron-Hadron Scattering |
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Abstract |
A measurement of jet activity in the rapidity interval bounded by a dijet system is presented. Events are vetoed if a jet with transverse momentum greater than 20 GeV is found between the two boundary jets. The fraction of dijet events that survive the jet veto is presented for boundary jets that are separated by up to six units of rapidity and with mean transverse momentum 50 < <(p)over bar>T < 500 GeV. The mean multiplicity of jets above the veto scale in the rapidity interval bounded by the dijet system is also presented as an alternative method for quantifying perturbative QCD emission. The data are compared to a next-to-leading order plus parton shower prediction from the POWHEG-BOX, an all-order resummation using the HEJ calculation and the PYTHIA, HERWIG++ and ALPGEN event generators. The measurement was performed using pp collisions at sqrt(s) = 7 TeV using data recorded by the ATLAS detector in 2010. |
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Address |
[Aad, G; Ahles, F; Beckingham, M; Bernhard, R; Bitenc, U; Bruneliere, R; Buckley, AG; Caron, S; Christov, A; Consorti, V; Eckert, S; Fehling-Kaschek, M; Flechl, M; Glatzer, J; Hartert, J; Herten, G; Horner, S; Jakobs, K; Ketterer, C; Kollefrath, M; Kononov, AI; Kuehn, S; Lai, S; Landgraf, U; Lohwasser, K; Ludwig, I; Ludwig, J; Lumb, D; Mahboubi, K; Meinhardt, J; Mohr, W; Nilsen, H; Parzefall, U; Rammensee, M; Runge, K; Rurikova, Z; Schmidt, E; Schumacher, M; Siegert, F; Stoerig, K; Sundermann, JE; Temming, KK; Thoma, S; Tobias, J; Tsiskaridze, V; Venturi, M; Vivarelli, I; von Radziewski, H; Warsinsky, M; Weiser, C; Werner, M; Wiik, LAM; Winkelmann, S; Xie, S; Zimmermann, S] Univ Freiburg, Fak Math & Phys, Freiburg, Germany |
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Corporate Author |
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Thesis |
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Publisher |
Springer |
Place of Publication |
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Editor |
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Language |
English |
Summary Language |
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Original Title |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
1126-6708 |
ISBN |
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Medium |
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Area |
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Expedition |
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Conference |
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Notes |
WOS:000296087000020 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ elepoucu @ |
Serial |
825 |
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Permanent link to this record |
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Author |
Degiovanni, A.; Amaldi, U.; Bonomi, R.; Garlasche, M.; Garonna, A.; Verdu-Andres, S.; Wegner, R. |
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Title |
TERA high gradient test program of RF cavities for medical linear accelerators |
Type |
Journal Article |
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Year |
2011 |
Publication |
Nuclear Instruments & Methods in Physics Research A |
Abbreviated Journal |
Nucl. Instrum. Methods Phys. Res. A |
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Volume |
657 |
Issue |
1 |
Pages |
55-58 |
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Keywords |
Medical accelerators; Hadrontherapy; Cyclinac; Linac; RF cavity; Breakdown Rate |
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Abstract |
The scientific community and the medical industries are putting a considerable effort into the design of compact, reliable and cheap accelerators for hadrontherapy. Up to now only circular accelerators are used to deliver beams with energies suitable for the treatment of deep seated tumors. The TERA Foundation has proposed and designed a hadrontherapy facility based on the cyclinac concept: a high gradient linear accelerator placed downstream of a cyclotron used as an injector. The overall length of the linac, and therefore its final cost, is almost inversely proportional to the average accelerating gradient achieved in the linac. TERA, in collaboration with the CLIC RF group, has started a high gradient test program. The main goal is to study the high gradient behavior of prototype cavities and to determine the appropriate linac operating frequency considering important issues such as machine reliability and availability of distributed power sources. A preliminary test of a 3 GHz cavity has been carried out at the beginning of 2010, giving encouraging results. Further investigations are planned before the end of 2011. A set of 5.7 GHz cavities is under production and will be tested in a near future. The construction and test of a multi-cell structure is also foreseen. |
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Address |
[Degiovanni, A; Wegner, R] CERN, CH-1211 Geneva, Switzerland, Email: alberto.degiovanni@cern.ch |
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Corporate Author |
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Thesis |
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Publisher |
Elsevier Science Bv |
Place of Publication |
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Editor |
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Language |
English |
Summary Language |
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Original Title |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0168-9002 |
ISBN |
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Medium |
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Area |
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Expedition |
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Conference |
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Notes |
WOS:000297085800010 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ elepoucu @ |
Serial |
807 |
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Permanent link to this record |
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Author |
Kuhn, J.H.; Rodrigo, G. |
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Title |
Charge asymmetries of top quarks at hadron colliders revisited |
Type |
Journal Article |
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Year |
2012 |
Publication |
Journal of High Energy Physics |
Abbreviated Journal |
J. High Energy Phys. |
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Volume |
01 |
Issue |
1 |
Pages |
063 - 25pp |
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Keywords |
Heavy Quark Physics; Hadronic Colliders; Standard Model; Beyond Standard Model |
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Abstract |
A sizeable difference in the differential production cross section of top-compared to antitop-quark production, denoted charge asymittetm has been observed at the Tevatron. The experimental results seem to exceed the theory predictions based on the Standard Model by a significant amount and have triggered a large number of suggestions for “new physics'. In the present paper the Standard Model predictions for Tevatron and LHe experiments are revisited. This includes a reanalysis of electromagnetic as well as weak corrections, leading to a shift of the asymmetry by roughly a factor 1.1 when compared to the results of the first papers on this subject. The impact of cuts on the transverse momentum of the top-antitop system is studied. Restricting the it system to a transverse momentum less than 20 GeV leads to an enhancement of the asymmetries by factors between 1.3 and 1.5, indicating the importance of an improved understanding of the tt-momentum distribution. Predictions for similar measurements at the LHC are presented, demonstrating the sensitivity of the large rapidity region bot ti to the Standard Model contribution and effects from ”new physics". |
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Address |
[Kuehn, Johann H.] Karlsruher Inst Technol, Inst Theoret Teilchenphys, D-76133 Karlsruhe, Germany, Email: johann.kuehn@kit.edu |
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Corporate Author |
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Thesis |
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Publisher |
Springer |
Place of Publication |
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Editor |
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Language |
English |
Summary Language |
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Original Title |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
1126-6708 |
ISBN |
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Medium |
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Area |
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Expedition |
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Conference |
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Notes |
WOS:000300181800063 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
971 |
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Permanent link to this record |