867 research outputs found
Effect of the smaller mass-squared difference for the long base-line neutrino experiments
Usually, neutrino oscillation experiments are analyzed within the two-flavor
framework which is governed by 1 mass-squared difference and 1 mixing angle.
But there are 6 parameters,2 mass-squared differences, 3 mixing angles, and 1
CP phase within the three-flavor framework.In this article,we estimate the
effect from the smaller mass-squared difference,the other mixing angles, and
the CP phase, which we call three-flavor effect, for the determination of the
mass-squared difference and the mixing angle from the nu_mu's survival and
transition probability with the two-flavor analysis.It is found that the
mass-squared difference from the two-flavor analysis is slightly shifted from
the larger mass-squared difference by the three-flavor effect.The order of
magnitude of the three-flavor effect for the mass-squared difference is
comparable with that of the expected error for the mass-squared difference of
the two-flavor analysis in the future long base-line neutrino oscillation
experiments.The CP phase dependence of the nu_mu to nu_etransition probability
is also shown.Comment: 13 pages, no figure new reference added, correct typos, Accepted by
Progress of Theoretical Physic
Re-evaluation of the T2KK physics potential with simulations including backgrounds
The Tokai-to-Kamioka-and-Korea (T2KK) neutrino oscillation experiment under
examination can have a high sensitivity to determine the neutrino mass
hierarchy for a combination of relatively large (\sim 3.0^circ) off-axis angle
beam at Super-Kamiokande (SK) and small (\sim 0.5^circ) off-axis angle at L
\sim 1,000km in Korea. We elaborate previous studies by taking into account
smearing of reconstructed neutrino energy due to finite resolution of electron
or muon energies, nuclear Fermi motion and resonance production, as well as the
neutral current \pi^0 production background to the nu_mu to nu_e oscillation
signal. It is found that the mass hierarchy pattern can still be determined at
3sigma level if sin^22thata_rct \quiv 4|U_{e3}|^2(1-|U_{e3}|^2) \gsim
0.08(0.09) when the hierarchy is normal (inverted) with 5 \times10^{21} POT
exposure, or 5 years of the T2K experiment, if a 100kton water cherenkov
detector is placed in Korea. The \pi^0 backgrounds deteriorate the capability
of the mass hierarchy determination, whereas the events from nuclear resonance
productions contribute positively to the hierarchy discrimination power. We
also find that the \pi^0 backgrounds seriously affect the CP phase measurement.
Although \delta_mns can still be constrained with an accuracy of \sim \pm
45^circ (\pm 60^circ) at 1sigma level for the normal (inverted) hierarchy with
the above exposure if sin^22theta_rct \gsim 0.04, CP violation can no longer be
established at 3sigma level even for delta_mns=\pm 90^circ and
sin^22theta_rct=0.1. About four times higher exposure will be needed to measure
delta_mns with \pm 30^circ accuracy.Comment: 46 pages, 13 figure
Solving the neutrino parameter degeneracy by measuring the T2K off-axis beam in Korea
The T2K neutrino oscillation experiment will start in 2009. In this
experiment the center of the neutrino beam from J-PARC at Tokai village will go
through underground beneath Super-Kamiokande, reach the sea level east of
Korean shore, and an off-axis beam at to can be
observed in Korea. We study physics impacts of putting a 100 kt-level Water
\cerenkov detector in Korea during the T2K experimental period. For a
combination of the off-axis beam at SK with baseline length L = 295
km and the off-axis beam in the east coast of Korea at L = 1000
km, we find that the neutrino mass hierarchy (the sign of )
can be resolved and the CP phase of the MNS unitary matrix can be constrained
uniquely at 3- level when \sin^2 2\theta_{\rm rct}
The structure and the evolution of essential patents for standards: Lessons from three IT standards
This paper examines the structure and the evolution of the patents declared as essential for three major technical standards in information technology (MPEG2, DVD and W-CDMA). These standards have many essential patents, which are owned by many firms with different interests. Many patents have been applied even after the standard was set. We analyze three important reasons for why the essential patents are many and increase over time: they cover a number of different technology fields, there exist R&D competition even in a narrowly defined technology field and a firm can expand its patent portfolio by using continuations and other practices based on the priority dates of its earlier filed patent applications in the USA. Around 40% of the essential US patents for MPEG2 and DVD standards have been obtained by using these applications. However, our empirical analysis suggests that a firm with pioneering patents does not obtain more essential patents, using these practices.standard, essential patent, continuations
Revisiting T2KK and T2KO physics potential and - beam ratio
We revisit the sensitivity study of the Tokai-to-Kamioka-and-Korea (T2KK) and
Tokai-to-Kamioka-and-Oki (T2KO) proposals where a water Cerenkov detector with
the 100 kton fiducial volume is placed in Korea ( km) and Oki island
( km) in Japan, respectively, in addition to the Super-Kamiokande for
determination of the neutrino mass hierarchy and leptonic CP phase
(). We systematically study the running ratio of the and
focusing beams with dedicated background estimation for the
appearance and disappearance signals, especially improving
treatment of the neutral current backgrounds. Using a -
beam ratio between 3 : 2 and 2.5 : 2.5 (in unit of POT
with the proton energy of 40 GeV), the mass hierarchy determination with the
median sensitivity of 3 - 5 by the T2KK and 1 - 4 by the T2KO
experiment are expected when , depending on the mass
hierarchy pattern and CP phase. These sensitivities are enhanced (reduced) by
- in when . The
CP phase is measured with the uncertainty of - by the
T2KK and T2KO using the - focusing beam ratio between
3.5 : 1.5 and 1.5 : 3.5. These findings indicate that inclusion of the
focusing beam improves the sensitivities of the T2KK and T2KO
experiments to both the mass hierarchy determination and leptonic CP phase
measurement simultaneously with the preferred beam ratio being between 3 : 2 -
2.5 : 2.5 (POT).Comment: 33 pages, 16 figures, 5 table
- …