5,520 research outputs found

    Charged-Current Disappearance Measurements in the NuMI Off-Axis Beam

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    This article studies the potential of combining charged-current disappearance measurements of \nu_{\mu} to \nu_{\tau} from MINOS and an off-axis beam. I find that the error on \Delta m^2 from a 100 kt-yr off-axis measurement is a few percent of itself. Further, I find little improvement to an off-axis measurement by combining it with MINOS.Comment: Presented at NuFact'02. Four pages, three figure

    Same-sign WW scattering in the HEFT: discoverability vs. EFT validity

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    Vector boson scatterings are fundamental processes to shed light on the nature of the electroweak symmetry breaking mechanism. Deviations from the Standard Model predictions on the corresponding observables can be interpreted in terms of effective field theories, that however undergo consistency conditions. In this paper, the same-sign W W scattering is considered within the HEFT context and the correct usage of the effective field theory approach is discussed. Regions of the parameters space are identified where a signal of new physics could be measured at HL-LHC with a significance of more than 5蟽 and the effective field theory description is consistently adopted. These results are then translated into bounds on the 尉 parameter in the composite Higgs scenario. The discussion on the agreement with previous literature and the comparison with the equivalent analysis in the SMEFT case are also included.The work of P.K. is supported by the Spanish MINECO project FPA2016-78220-C3-1-P (Fondos FEDER) and by National Science Centre, Poland, the PRELUDIUM project under contract 2018/29/N/ST2/01153. L.M. acknowledges partial nancial support by the Spanish MINECO through the \Ram贸n y Cajal" programme (RYC-2015-17173), by the Spanish \Agencia Estatal de Investigaci贸n" (AEI) and the EU \Fondo Europeo de Desarrollo Regional" (FEDER) through the project FPA2016-78645-P, and through the Centro de excelencia Severo Ochoa Program under grant SEV-2016-0597, and by the European Union's Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie grant agreements No 690575 and No 674896. The work of S.P. is partially supported by the National Science Centre, Poland, under research grants DEC-2015/18/M/ST2/00054 and DEC-2016/23/G/ST2/04301. M.S. is partially supported by the generous COST grant, COST Action No. CA16108 (VBSCan). L.M. thanks the Institute of Theoretical Physics of the University of Warsaw for hospitality during the development of this project. S.P. thanks the Instituto de F铆sica Te贸rica (IFT UAM-CSIC) in Madrid for its support via the Centro de Excelencia Severo Ochoa Program under Grant SEV-2016-0597

    Complementarity of a Low Energy Photon Collider and LHC Physics

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    We discuss the complementarity between the LHC and a low energy photon collider. We mostly consider the scenario, where the first linear collider is a photon collider based on dual beam technology like CLIC.Comment: 29 pages, 37 figure, LP-200

    Ground Motion Studies at NuMI

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    Ground motion can cause significant deterioration in the luminosity of a linear collider. Vibration of numerous focusing magnets causes continuous misalignments, which makes the beam emittance grow. For this reason, understanding the seismic vibration of all potential LC sites is essential and related efforts in many sites are ongoing. In this document we summarize the results from the studies specific to Fermilab grounds as requested by the LC project leader at FNAL, Shekhar Mishra in FY04-FY06. The Northwestern group focused on how the ground motion effects vary with depth. Knowledge of depth dependence of the seismic activity is needed in order to decide how deep the LC tunnel should be at sites like Fermilab. The measurements were made in the NuMI tunnel, see Figure 1. We take advantage of the fact that from the beginning to the end of the tunnel there is a height difference of about 350 ft and that there are about five different types of dolomite layers. The support received allowed to pay for three months of salary of Michal Szleper. During this period he worked a 100% of his time in this project. That include one week of preparation: 2.5 months of data taking and data analysis during the full period of the project in order to guarantee that we were recording high quality data. We extended our previous work and made more systematic measurements, which included detailed studies on stability of the vibration amplitudes at different depths over long periods of time. As a consequence, a better control and more efficient averaging out of the daytime variation effects were possible, and a better study of other time dependences before the actual depth dependence was obtained. Those initial measurements were made at the surface and are summarized in Figure 2. All measurements are made with equipment that we already had (two broadband seismometers KS200 from GEOTECH and DL-24 portable data recorder). The offline data analysis took advantage of the full Fourier spectra information and the noise was properly subtracted. The basic formalism is summarized if Figure 3. The second objective was to make a measurement deeper under ground (Target hall, Absorber hall and Minos hall - 150 ft to 350 ft), which previous studies did not cover. All results are summarized in Figure 3 and 4. The measurements were covering a frequency range between 0.1 to 50 Hz. The data was taken continuously for at least a period of two weeks in each of the locations. We concluded that the dependence on depth is weak, if any, for frequencies above 1 Hz and not visible at all at lower frequencies. Most of the attenuation (factor of about 2-3) and damping of ground motion that is due to cultural activity at the surface is not detectable once we are below 150 ft underground. Therefore, accelerator currently under consideration can be build at the depth and there is no need to go deeper underground is built at Fermi National Laboratory

    The Physics Potential of Future Long Baseline Neutrino Oscillation Experiments

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    We discuss in detail different future long baseline neutrino oscillation setups and we show the remarkable potential for very precise measurements of mass splittings and mixing angles. Furthermore it will be possible to make precise tests of coherent forward scattering and MSW effects, which allow to determine the sign of m2\Delta m^2. Finally strong limits or measurements of leptonic CP violation will be possible, which is very interesting since it is most likely connected to the baryon asymmetry of the universe.Comment: 32 pages, 15 figures, to appear in ``Neutrino Mass'', Springer Tracts in Modern Physics, ed. by G. Altarelli and K. Winter, references adde