| 1. |
- Akhmedov, Evgeny K., et al.
(författare)
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Series expansions for three-flavor neutrino oscillation probabilities in matter
- 2004
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Ingår i: Journal of High Energy Physics (JHEP). - : IOP Publishing. - 1126-6708 .- 1029-8479. ; 2004:04, s. 078-
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Tidskriftsartikel (refereegranskat)abstract
- We present a number of complete sets of series expansion formulas for neutrino oscillation probabilities in matter of constant density for three flavors. In particular, we study expansions in the mass hierarchy parameter alpha = Deltam(21)(2)/Deltam(31)(2) and mixing parameter s(13) = sin theta(13) up to second order and expansions only in alpha and only in s(13) up to first order. For each type of expansion we also present the corresponding formulas for neutrino oscillations in vacuum. We perform a detailed analysis of the accuracy of the different sets of series expansion formulas and investigate which type of expansion is most accurate in different regions of the parameter space spanned by the neutrino energy E, the baseline length L, and the expansion parameters alpha and s(13). We also present the formulas for series expansions in alpha and in s(13) up to first order for the case of arbitrary matter density profiles. Furthermore, it is shown that in general all the 18 neutrino and antineutrino oscillation probabilities can be expressed through just two independent probabilities.
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| 2. |
- Alekseev, AY, et al.
(författare)
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Brane dynamics in background fluxes and non-commutative geometry
- 2000
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Ingår i: JOURNAL OF HIGH ENERGY PHYSICS. - : EDITRICE COMPOSITORI BOLOGNA. - 1029-8479. ; 2000:5, s. U188-U212
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Tidskriftsartikel (refereegranskat)abstract
- Branes in non-trivial backgrounds are expected to exhibit interesting dynamical properties. We use the boundary conformal field theory approach to study branes in a curved background with non-vanishing Neveu-Schwarz 3-form field strength. For branes on an
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| 3. |
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| 4. |
- Alwall, Johan, et al.
(författare)
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Improved description of charged Higgs boson production at hadron colliders
- 2004
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Ingår i: Journal of High Energy Physics. - : Springer Science and Business Media LLC. - 1029-8479. ; 0412:050
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Tidskriftsartikel (refereegranskat)abstract
- We present a new method for matching the two twin-processes gb→H±t and gg→H±tb in Monte Carlo event generators. The matching is done by defining a double-counting term, which is used to generate events that are subtracted from the sum of these two twin-processes. In this way we get a smooth transition between the collinear region of phase space, which is best described by gb→H±t, and the hard region, which requires the use of the gg→H±tb process. The resulting differential distributions show large differences compared to both the gb→H±t and gg→H±tb processes illustrating the necessity to use matching when tagging the accompanying b-jet.
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| 5. |
- Bachas, Constantin, et al.
(författare)
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Nahm's equations, {$\scr N=1^*$} domain walls, and {D}-strings in {${\rm AdS}_5\times S_5$}
- 2001
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Ingår i: Journal of High Energy Physics (JHEP). - : Springer Science and Business Media LLC. - 1126-6708 .- 1029-8479. ; :7, s. Paper 41,28-
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Tidskriftsartikel (refereegranskat)abstract
- We consider the following two problems: classical domain walls in the = 1* mass deformation of the maximally supersymmetric Yang Mills theory, and D-strings as external magnetic sources in the context of the AdS/CFT correspondence. We show that they are both described by Nahm's equations with unconventional boundary conditions, and analyze the relevant moduli space of solutions. We argue that general `fuzzy sphere' configurations of D-strings in AdS5 correspond to Wilson-'t Hooft lines in higher representations of the dual SU(n) gauge theory.
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| 6. |
- Bijnens, Johan, et al.
(författare)
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Large extra dimensions in rare decays
- 2000
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Ingår i: Journal of High Energy Physics. - : Springer Science and Business Media LLC. - 1029-8479. ; 2000:JHEP10(2000)
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Tidskriftsartikel (refereegranskat)abstract
- The prospect of experimental verification of the large extra dimension scenario in rare decays is discussed. The case of J/ψ and γ to photon + missing energy is calculated in detail, and it is shown that the limit on the compactification scale MS lies at present in the ten GeV range. In contrast to the quarkonium systems, signals in Kaon and Pion decays will be small.
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| 7. |
- Bijnens, Johan, et al.
(författare)
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Matching the electroweak penguins q7, q8 and spectral correlators
- 2001
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Ingår i: Journal of High Energy Physics. - : Springer Science and Business Media LLC. - 1029-8479. ; 2001:JHEP10(2001)
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Tidskriftsartikel (refereegranskat)abstract
- Exact analytical expressions for the ∆S = 1 coupling Im GE in terms of observable spectral functions are given. This coupling determines the size of the ∆I = 3/2 contribution to ε′ . We show analytically how the scheme-dependence and scale dependences vanish to all orders in 1/Nc and NLO in αS explicitly both for Q7 and Q8 . Numerical results are derived for both Q7 and Q8 from the τ-data and known results on the scalar spectral functions. In particular we study the effect of all higher dimension operators. The coefficients of the leading operators in the OPE of the needed correlators are derived to NLO in αS .
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| 8. |
- Bijnens, Johan, et al.
(författare)
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pi K scattering in three flavour ChPT : π K scattering in three flavour ChPT
- 2004
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Ingår i: Journal of High Energy Physics. - : Springer Science and Business Media LLC. - 1029-8479. ; 2004:JHEP05(2004), s. 811-833
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Tidskriftsartikel (refereegranskat)abstract
- We present the scattering lengths for the piK processes in the three flavour Chiral Perturbation Theory (ChPT) framework at next-to-next-to-leading order (NNLO). The calculation has been performed analytically but we only include analytical results for the dependence on the low-energy constants (LECs) at NNLO due to the size of the expressions. These results, together with resonance estimates of the NNLO LECs are used to obtain constraints on the Zweig rule suppressed LECs at NLO, L-4(r) and L-6(r). Contrary to expectations from NLO order calculations we find them to be compatible with zero. We do a preliminary study of combining the results from pipi scattering, piK scattering and the scalar form-factors and find only a marginal compatibility with all experimental/dispersive input data.
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| 9. |
- Bijnens, Johan, et al.
(författare)
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Pi pi scattering in three flavor ChPT : ππ scattering in three flavour ChPT
- 2004
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Ingår i: Journal of High Energy Physics. - : Springer Science and Business Media LLC. - 1029-8479. ; 05:JHEP01(2004)
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Tidskriftsartikel (refereegranskat)abstract
- We present the scattering lengths for the pi-pi processes in the three flavour Chiral Perturbation Theory (ChPT) framework at next-to-next-to-leading order. We then combine this calculation with the determination of the parameters from $Ke4 and the masses and decay constants and compare with the results of a dispersive analysis of pi-pi scattering. The comparison indicates a small but nonzero value for the 1/Nc suppressed NLO low energy constants L4r and L6r.
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| 10. |
- Bijnens, Johan, et al.
(författare)
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Pion and kaon electromagnetic form factors
- 2002
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Ingår i: Journal of High Energy Physics. - : Springer Science and Business Media LLC. - 1029-8479. ; :3
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Tidskriftsartikel (refereegranskat)abstract
- We study the electromagnetic form factor of the pion and kaons at low-energies with the use of Chiral Perturbation Theory. The analysis is performed within the three flavour framework and at next-to-next-to-leading order. We explain carefully all the relevant consistency checks on the expressions, present full analytical results for the pion form factor and describe all the assumptions in the analysis. From the phenomenological point of view we make use of our expression and the available data to obtain the charge radius of the pion obtaining [r(2)](V)(pi) = (0.452 +/- 0.013)fm(2), as well as the low-energy constant L-9(r) (m(rho)) = (5.93 +/- 0.43) x 10(3). We also obtain experimental values for 3 combinations of O(p(6)) constants.
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