| Records |
| Author |
ATLAS Collaboration (Aad, G. et al); Alvarez Piqueras, D.; Cabrera Urban, S.; Castillo Gimenez, V.; Cerda Alberich, L.; Costa, M.J.; Fernandez Martinez, P.; Ferrer, A.; Fiorini, L.; Fuster, J.; Garcia, C.; Garcia Navarro, J.E.; Gonzalez de la Hoz, S.; Hernandez Jimenez, Y.; Higon-Rodriguez, E.; Irles Quiles, A.; Jimenez Pena, J.; Kaci, M.; King, M.; Lacasta, C.; Lacuesta, V.R.; Marti-Garcia, S.; Mitsou, V.A.; Pedraza Lopez, S.; Perez Garcia-Estañ, M.T.; Romero Adam, E.; Ros, E.; Salt, J.; Sanchez Martinez, V.; Soldevila, U.; Sanchez, J.; Valero, A.; Valls Ferrer, J.A.; Vos, M. |
| Title |
Measurement of the differential cross-section of highly boosted top quarks as a function of their transverse momentum in root s=8 TeV proton-proton collisions using the ATLAS detector |
Type |
Journal Article |
| Year |
2016 |
Publication |
Physical Review D |
Abbreviated Journal |
Phys. Rev. D |
| Volume |
93 |
Issue |
3 |
Pages |
032009 - 34pp |
| Keywords |
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| Abstract |
The differential cross-section for pair production of top quarks with high transverse momentum is measured in 20.3 fb(-1) of proton-proton collisions at a center-of-mass energy of 8 TeV. The measurement is performed for t (t) over bar events in the lepton + jets channel. The cross-section is reported as a function of the hadronically decaying top quark transverse momentum for values above 300 GeV. The hadronically decaying top quark is reconstructed as an anti-k(t) jet with radius parameter R = 1.0 and identified with jet substructure techniques. The observed yield is corrected for detector effects to obtain a cross-section at particle level in a fiducial region close to the event selection. A parton-level cross-section extrapolated to the full phase space is also reported for top quarks with transverse momentum above 300 GeV. The predictions of a majority of next-to-leading-order and leading-order matrix-element Monte Carlo generators are found to agree with the measured cross-sections. |
| Address |
[Corriveau, F.; Jackson, P.; Lee, L.; McPherson, R. A.; Petridis, A.; Robertson, S. H.; Sobie, R.; Soni, N.; Teuscher, R. J.; White, M. J.] Univ Adelaide, Dept Phys, Adelaide, SA, Australia |
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| Publisher |
Amer Physical Soc |
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English |
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| ISSN |
2470-0010 |
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Conference |
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| Notes |
WOS:000385749200001 |
Approved |
no |
| Is ISI |
yes |
International Collaboration |
yes |
| Call Number |
IFIC @ pastor @ |
Serial |
2851 |
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| Author |
Alekhin, S. et al; Hernandez, P. |
| Title |
A facility to search for hidden particles at the CERN SPS: the SHiP physics case |
Type |
Journal Article |
| Year |
2016 |
Publication |
Reports on Progress in Physics |
Abbreviated Journal |
Rep. Prog. Phys. |
| Volume |
79 |
Issue |
12 |
Pages |
124201 - 137pp |
| Keywords |
beyond the standard model physics; intensity frontier experiment; hidden sectors; heavy neutral leptons; dark photons |
| Abstract |
This paper describes the physics case for a new fixed target facility at CERN SPS. The SHiP (search for hidden particles) experiment is intended to hunt for new physics in the largely unexplored domain of very weakly interacting particles with masses below the Fermi scale, inaccessible to the LHC experiments, and to study tau neutrino physics. The same proton beam setup can be used later to look for decays of tau-leptons with lepton flavour number non-conservation, tau -> 3 μand to search for weakly-interacting sub-GeV dark matter candidates. We discuss the evidence for physics beyond the standard model and describe interactions between new particles and four different portals-scalars, vectors, fermions or axion-like particles. We discuss motivations for different models, manifesting themselves via these interactions, and how they can be probed with the SHiP experiment and present several case studies. The prospects to search for relatively light SUSY and composite particles at SHiP are also discussed. We demonstrate that the SHiP experiment has a unique potential to discover new physics and can directly probe a number of solutions of beyond the standard model puzzles, such as neutrino masses, baryon asymmetry of the Universe, dark matter, and inflation. |
| Address |
[Alekhin, Sergey] DESY, Platanenallee 6, D-15738 Zeuthen, Germany, Email: oleg.ruchayskiy@cern.ch |
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Iop Publishing Ltd |
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English |
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0034-4885 |
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| Notes |
WOS:000387025400001 |
Approved |
no |
| Is ISI |
yes |
International Collaboration |
yes |
| Call Number |
IFIC @ pastor @ |
Serial |
2852 |
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| Author |
Sborlini, G.F.R.; Driencourt-Mangin, F.; Rodrigo, G. |
| Title |
Four-dimensional unsubtraction with massive particles |
Type |
Journal Article |
| Year |
2016 |
Publication |
Journal of High Energy Physics |
Abbreviated Journal |
J. High Energy Phys. |
| Volume |
10 |
Issue |
10 |
Pages |
162 - 34pp |
| Keywords |
NLO Computations |
| Abstract |
We extend the four-dimensional unsubtraction method, which is based on the loop-tree duality (LTD), to deal with processes involving heavy particles. The method allows to perform the summation over degenerate IR configurations directly at integrand level in such a way that NLO corrections can be implemented directly in four space-time dimensions. We define a general momentum mapping between the real and virtual kinematics that accounts properly for the quasi-collinear configurations, and leads to an smooth massless limit. We illustrate the method first with a scalar toy example, and then analyse the case of the decay of a scalar or vector boson into a pair of massive quarks. The results presented in this paper are suitable for the application of the method to any multipartonic process. |
| Address |
[Sborlini, German F. R.; Driencourt-Mangin, Felix; Rodrigo, German] Univ Valencia, CSIC, Inst Fis Corpuscular, Parc Cient, E-46980 Valencia, Spain, Email: german.sborlini@ific.uv.es; |
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Springer |
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English |
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1029-8479 |
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Conference |
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| Notes |
WOS:000387374000001 |
Approved |
no |
| Is ISI |
yes |
International Collaboration |
no |
| Call Number |
IFIC @ pastor @ |
Serial |
2853 |
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| Author |
Bayar, M.; Aceti, F.; Guo, F.K.; Oset, E. |
| Title |
Discussion on triangle singularities in the Lambda(b) -> J/psi K(-)p reaction |
Type |
Journal Article |
| Year |
2016 |
Publication |
Physical Review D |
Abbreviated Journal |
Phys. Rev. D |
| Volume |
94 |
Issue |
7 |
Pages |
074039 - 10pp |
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| Abstract |
We have analyzed the singularities of a triangle loop integral in detail and derived a formula for an easy evaluation of the triangle singularity on the physical boundary. It is applied to the Lambda(b) -> J/psi K(-)p process via Lambda*-charmonium-proton intermediate states. Although the evaluation of absolute rates is not possible, we identify the chi(c1) and the psi(2S)as the relatively most relevant states among all possible charmonia up to the psi(2S). The Lambda(1890)chi(c1)p loop is very special, as its normal threshold and triangle singularities merge at about 4.45 GeV, generating a narrow and prominent peak in the amplitude in the case that the chi(c1)p is in an S wave. We also see that loops with the same charmonium and other Lambda* hyperons produce less dramatic peaks from the threshold singularity alone. For the case of chi(c1)p -> J/psi p and quantum numbers 3/2(-) or 5/2(+), one needs P and D waves, respectively, in the chi(c1)p, which drastically reduce the strength of the contribution and smooth the threshold peak. In this case, we conclude that the singularities cannot account for the observed narrow peak. In the case of 1/2(+), 3/2(-) quantum numbers, where chi(c1)p -> J/psi p can proceed in an S wave, the Lambda(1890)chi(c1)p triangle diagram could play an important role, though neither can assert their strength without further input from experiments and lattice QCD calculations. |
| Address |
[Bayar, Melahat] Kocaeli Univ, Dept Phys, TR-41380 Izmit, Turkey |
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Amer Physical Soc |
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English |
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Abbreviated Series Title |
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Series Issue |
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Edition |
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| ISSN |
2470-0010 |
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Expedition |
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Conference |
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| Notes |
WOS:000387256100003 |
Approved |
no |
| Is ISI |
yes |
International Collaboration |
yes |
| Call Number |
IFIC @ pastor @ |
Serial |
2854 |
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| Author |
Giusarma, E.; Gerbino, M.; Mena, O.; Vagnozzi, S.; Ho, S.; Freese, K. |
| Title |
Improvement of cosmological neutrino mass bounds |
Type |
Journal Article |
| Year |
2016 |
Publication |
Physical Review D |
Abbreviated Journal |
Phys. Rev. D |
| Volume |
94 |
Issue |
8 |
Pages |
083522 - 8pp |
| Keywords |
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| Abstract |
The most recent measurements of the temperature and low-multipole polarization anisotropies of the cosmic microwave background from the Planck satellite, when combined with galaxy clustering data from the Baryon Oscillation Spectroscopic Survey in the form of the full shape of the power spectrum, and with baryon acoustic oscillation measurements, provide a 95% confidence level (C.L.) upper bound on the sum of the three active neutrinos Sigma m(nu) < 0.183 eV, among the tightest neutrino mass bounds in the literature, to date, when the same data sets are taken into account. This very same data combination is able to set, at similar to 70% C.L., an upper limit on Sigma m(nu) of 0.0968 eV, a value that approximately corresponds to the minimal mass expected in the inverted neutrino mass hierarchy scenario. If high-multipole polarization data from Planck is also considered, the 95% C.L. upper bound is tightened to Sigma m(nu) < 0.176 eV. Further improvements are obtained by considering recent measurements of the Hubble parameter. These limits are obtained assuming a specific nondegenerate neutrino mass spectrum; they slightly worsen when considering other degenerate neutrino mass schemes. Low-redshift quantities, such as the Hubble constant or the reionization optical depth, play a very important role when setting the neutrino mass constraints. We also comment on the eventual shifts in the cosmological bounds on Sigma m(nu) when possible variations in the former two quantities are addressed. |
| Address |
[Giusarma, Elena; Ho, Shirley] Carnegie Mellon Univ, Dept Phys, McWilliams Ctr Cosmol, Pittsburgh, PA 15213 USA, Email: egiusarm@andrew.cmu.edu; |
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Thesis |
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| Publisher |
Amer Physical Soc |
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 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 |
2470-0010 |
ISBN |
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Expedition |
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Conference |
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| Notes |
WOS:000387120400003 |
Approved |
no |
| Is ISI |
yes |
International Collaboration |
yes |
| Call Number |
IFIC @ pastor @ |
Serial |
2855 |
| Permanent link to this record |
