| Records |
| Author |
ATLAS Collaboration (Aaboud, M. et al); Alvarez Piqueras, D.; Barranco Navarro, L.; Cabrera Urban, S.; Castillo Gimenez, V.; Cerda Alberich, L.; Costa, M.J.; Estrada Pastor, O.; Fernandez Martinez, P.; Ferrer, A.; Fiorini, L.; Fuster, J.; Garcia, C.; Garcia Navarro, J.E.; Gonzalez de la Hoz, S.; Higon-Rodriguez, E.; Jimenez Pena, J.; Lacasta, C.; Mamuzic, J.; Marti-Garcia, S.; Melini, D.; Mitsou, V.A.; Pedraza Lopez, S.; Rodriguez Bosca, S.; Rodriguez Rodriguez, D.; Romero Adam, E.; Salt, J.; Sanchez Martinez, V.; Soldevila, U.; Sanchez, J.; Valero, A.; Valls Ferrer, J.A.; Vos, M. |
| Title |
Identification and rejection of pile-up jets at high pseudorapidity with the ATLAS detector |
Type |
Journal Article |
| Year |
2017 |
Publication |
European Physical Journal C |
Abbreviated Journal |
Eur. Phys. J. C |
| Volume |
77 |
Issue  |
9 |
Pages |
580 - 32pp |
| Keywords |
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| Abstract |
The rejection of forward jets originating from additional proton-proton interactions (pile-up) is crucial for a variety of physics analyses at the LHC, including Standard Model measurements and searches for physics beyond the Standard Model. The identification of such jets is challenging due to the lack of track and vertex information in the pseudorapidity range vertical bar eta vertical bar > 2.5. This paper presents a novel strategy for forward pile-up jet tagging that exploits jet shapes and topological jet correlations in pile-up interactions. Measurements of the per-jet tagging efficiency are presented using a data set of 3.2 fb(-1) of proton-proton collisions at a centre-of-mass energy of 13 TeV collected with the ATLAS detector. The fraction of pile-up jets rejected in the range 2.5 < vertical bar eta vertical bar < 4.5 is estimated in simulated events with an average of 22 interactions per bunch-crossing. It increases with jet transverse momentum and, for jets with transverse momentum between 20 and 50 GeV, it ranges between 49% and 67% with an efficiency of 85% for selecting hard-scatter jets. A case study is performed in Higgs boson production via the vector-boson fusion process, showing that these techniques mitigate the background growth due to additional proton-proton interactions, thus enhancing the reach for such signatures. |
| Address |
[Chelkov, G. A.; Jackson, P.; Petridis, A.; White, M. J.] Univ Adelaide, Dept Phys, Adelaide, SA, Australia |
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| Publisher |
Springer |
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English |
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Series Issue |
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Edition |
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| ISSN |
1434-6044 |
ISBN |
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Expedition |
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Conference |
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| Notes |
WOS:000409355300002 |
Approved |
no |
| Is ISI |
yes |
International Collaboration |
yes |
| Call Number |
IFIC @ pastor @ |
Serial |
3288 |
| Permanent link to this record |
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| Author |
Alves, J.M.; Botella, F.J.; Branco, G.C.; Cornet-Gomez, F.; Nebot, M. |
| Title |
Controlled flavour changing neutral couplings in two Higgs Doublet models |
Type |
Journal Article |
| Year |
2017 |
Publication |
European Physical Journal C |
Abbreviated Journal |
Eur. Phys. J. C |
| Volume |
77 |
Issue |
9 |
Pages |
585 - 18pp |
| Keywords |
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| Abstract |
We propose a class of two Higgs doublet models where there are flavour changing neutral currents (FCNC) at tree level, but under control due to the introduction of a discrete symmetry in the full Lagrangian. It is shown that in this class of models, one can have simultaneously FCNC in the up and down sectors, in contrast to the situation encountered in the renormalisable and minimal flavour violating 2HDM models put forward by Branco et al. (Phys Lett B 380: 119, 1996). The intensity of FCNC is analysed and it is shown that in this class of models one can respect all the strong constraints from experiment without unnatural fine-tuning. It is pointed out that the additional sources of flavour and CP violation are such that they can enhance significantly the generation of the Bbaryon asymmetry of the Universe, with respect to the standard model. |
| Address |
[Alves, Joao M.; Branco, Gustavo C.; Nebot, Miguel] UL, IST, Dept Fis, Ave Rovisco Pais, P-1049001 Lisbon, Portugal, Email: j.magalhaes.alves@tecnico.ulisboa.pt; |
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Springer |
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English |
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Series Issue |
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Edition |
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| ISSN |
1434-6044 |
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:000409356700001 |
Approved |
no |
| Is ISI |
yes |
International Collaboration |
yes |
| Call Number |
IFIC @ pastor @ |
Serial |
3293 |
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| Author |
Barenboim, G.; Kinney, W.H.; Park, W.I. |
| Title |
Flavor versus mass eigenstates in neutrino asymmetries: implications for cosmology |
Type |
Journal Article |
| Year |
2017 |
Publication |
European Physical Journal C |
Abbreviated Journal |
Eur. Phys. J. C |
| Volume |
77 |
Issue |
9 |
Pages |
590 - 7pp |
| Keywords |
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| Abstract |
We show that, if they exist, lepton number asymmetries (L-alpha) of neutrino flavors should be distinguished from the ones (L-i) of mass eigenstates, since Big Bang Nucleosynthesis (BBN) bounds on the flavor eigenstates cannot be directly applied to the mass eigenstates. Similarly, Cosmic Microwave Background (CMB) constraints on the mass eigenstates do not directly constrain flavor asymmetries. Due to the difference of mass and flavor eigenstates, the cosmological constraint on the asymmetries of neutrino flavors can be much stronger than the conventional expectation, but they are not uniquely determined unless at least the asymmetry of the heaviest neutrino is well constrained. The cosmological constraint on L-i for a specific case is presented as an illustration. |
| Address |
[Barenboim, Gabriela; Park, Wan-Il] Univ Valencia, CSIC, Dept Fis Teor, E-46100 Burjassot, Spain, Email: Gabriela.Barenboim@uv.es; |
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| Publisher |
Springer |
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English |
Summary Language |
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Series Title |
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Abbreviated Series Title |
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Series Issue |
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Edition |
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| ISSN |
1434-6044 |
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:000410888500004 |
Approved |
no |
| Is ISI |
yes |
International Collaboration |
yes |
| Call Number |
IFIC @ pastor @ |
Serial |
3294 |
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| Author |
Pavao, R.P.; Sakai, S.; Oset, E. |
| Title |
Triangle singularities in B- -> D*(0)pi(-)pi(0)eta and B- -> D*(0)pi(-)pi(+)pi(-) |
Type |
Journal Article |
| Year |
2017 |
Publication |
European Physical Journal C |
Abbreviated Journal |
Eur. Phys. J. C |
| Volume |
77 |
Issue |
9 |
Pages |
599 - 8pp |
| Keywords |
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| Abstract |
The possible role of the triangle mechanism in the B- decay into D*(0)pi(-)pi(0)eta and D*(0)pi(-)pi(+)pi(-) is investigated. In this process, the triangle singularity appears from the decay of B- into D*K-0(-) K*(0) followed by the decay of K-*0 into pi(-) K+ and the fusion of the K+ K-, which forms the a(0)(980) or f(0)(980), which finally decay into pi(0)eta or pi(+)pi(-), respectively. The triangle mechanism from the (K) over bar * K (K) over bar loop generates a peak around 1420 MeV in the invariant mass of pi(-) a(0) or pi(-) f(0), and it gives sizable branching fractions, Br(B- -> D*(0)pi(-) a(0); a(0) -> pi(0)eta) = (1.66 +/- 0.45) x 10(-6) and Br(B- -> D*(0)pi(-) f(0); f(0) -> pi(+)pi(-)) = (2.82 +/- 0.75) x 10(-6). |
| Address |
[Pavao, R.; Sakai, S.; Oset, E.] Univ Valencia, CSIC, Inst Invest Paterna, Dept Fis Teor,Ctr Mixto, Aptdo 22085, Valencia 46071, Spain, Email: rpavao@ific.uv.es |
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Springer |
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English |
Summary Language |
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Series Title |
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Abbreviated Series Title |
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Series Issue |
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Edition |
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| ISSN |
1434-6044 |
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:000410891900001 |
Approved |
no |
| Is ISI |
yes |
International Collaboration |
no |
| Call Number |
IFIC @ pastor @ |
Serial |
3297 |
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| Author |
Marco-Hernandez, R.; Bau, M.; Ferrari, M.; Ferrari, V.; Pedersen, F.; Soby, L. |
| Title |
A Low-Noise Charge Amplifier for the ELENA Trajectory, Orbit, and Intensity Measurement System |
Type |
Journal Article |
| Year |
2017 |
Publication |
IEEE Transactions on Nuclear Science |
Abbreviated Journal |
IEEE Trans. Nucl. Sci. |
| Volume |
64 |
Issue |
9 |
Pages |
2465-2473 |
| Keywords |
Beam position monitor (BPM); charge sensitive amplifier; instrumentation for accelerators; low-noise amplifier; particle accelerators; printed circuits |
| Abstract |
A low-noise head amplifier has been developed for the extra low energy antiproton ring beam trajectory, orbit, and intensity measurement system at CERN. This system is based on 24 double-electrode electrostatic beam position monitors installed around the ring. A head amplifier is placed close to each beam position monitor to amplify the electrode signals and generate a difference and a sum signal. These signals are sent to the digital acquisition system, about 50 m away from the ring, where they are digitized and further processed. The beam position can be measured by dividing the difference signal by the sum signal while the sum signal gives information relative to the beam intensity. The head amplifier consists of two discrete charge preamplifiers with junction field effect transistor (JFET) inputs, a sum and a difference stage, and two cable drivers. Special attention has been paid to the amplifier printed circuit board design to minimize the parasitic capacitances and inductances at the charge amplifier stages to meet the gain and noise requirements. The measurements carried out on the head amplifier showed a gain of 40.5 and 46.5 dB for the sum and difference outputs with a bandwidth from 200 Hz to 75 MHz and an input voltage noise density lower than 400 pV/v Hz. Twenty head amplifiers have been already installed in the ring and they have been used to detect the first beam signals during the first commissioning stage in November 2016. |
| Address |
[Marco-Hernandez, Ricardo; Pedersen, Flemming; Soby, Lars] CERN, CH-1217 Meyrin, Switzerland, Email: rmarco@ific.uv.es |
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Thesis |
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| Publisher |
Ieee-Inst Electrical Electronics Engineers Inc |
Place of Publication |
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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 Issue |
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Edition |
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| ISSN |
0018-9499 |
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:000411029500002 |
Approved |
no |
| Is ISI |
yes |
International Collaboration |
yes |
| Call Number |
IFIC @ pastor @ |
Serial |
3298 |
| Permanent link to this record |
