| 1. |
- Blennow, Mattias, 1980-, et al.
(författare)
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Non-standard interaction effects on astrophysical neutrino fluxes
- 2009
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Ingår i: Physical Review D. - 1550-7998 .- 1550-2368. ; 80:6, s. 065009-
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Tidskriftsartikel (refereegranskat)abstract
- We investigate new physics effects in the production and detection of high-energy neutrinos at neutrino telescopes. Analyzing the flavor ratios ϕμ/ϕτ and ϕμ/(ϕτ+ϕe), we find that the standard model predictions for them can be sensibly altered by new physics effects in the case of pion sources. However, the experimental precision required to see the effects would be very difficult to obtain.
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| 2. |
- Blennow, Mattias, et al.
(författare)
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Non-standard interactions using the OPERA experiment
- 2008
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Ingår i: European Physical Journal C. - : Springer-Verlag / Società Italiana di Fisica. - 1434-6044 .- 1434-6052. ; 56:4, s. 529-536
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Tidskriftsartikel (refereegranskat)abstract
- We investigate the implications of non-standard interactions on neutrino oscillations in the OPERA experiment. In particular, we study the non-standard interaction parameter epsilon(mu tau) . We show that the OPERA experiment has a unique opportunity to reduce the allowed region for this parameter compared with other experiments such as the MINOS experiment, mostly due to the higher neutrino energies in the CNGS beam compared to the NuMI beam. We find that OPERA is mainly sensitive to a combination of standard and non-standard parameters and that a resulting anti-resonance effect could suppress the expected number of events. Furthermore, we show that running OPERA for five years each with neutrinos and anti-neutrinos would help in resolving the degeneracy between the standard parameters and epsilon(mu tau) . This scenario is significantly better than the scenario with a simple doubling of the statistics by running with neutrinos for ten years.
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| 3. |
- Carfi, A., et al.
(författare)
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Bone mineral density in adults with Down syndrome
- 2017
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Ingår i: Osteoporosis International. - : Springer Science and Business Media LLC. - 0937-941X .- 1433-2965. ; 28:10, s. 2929-2934
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Tidskriftsartikel (refereegranskat)abstract
- SummaryThis study analyzed data of bone mineral density (BMD) from a large cohort of adults with Down syndrome (DS). BMD was found to decrease with age more rapidly in these subjects than in the general population, exposing adults with DS to an increased risk of osteoporosis and bone fracture.IntroductionDown syndrome (DS) in adulthood presents with a high prevalence of osteoporosis. However, in DS, bone mineral density (BMD) can be underestimated due to short stature. Furthermore, the rate of age-related decline in BMD and its association with gender in DS has been rarely evaluated or compared with the general population. The present study is aimed at assessing the variation of BMD with age and gender in a sample of adults with DS and to compare these data with those of the general population, after adjusting for anthropometric differences.MethodsAdults with DS, aged 18 or older, were assessed dual-energy-X-ray-absorptiometry (DXA) at the femoral neck and at the lumbar spine. They were compared with the general population enrolled in the National Health and Nutrition Examination Survey (NHANES) 2009-2010 dataset. Bone mineral apparent density (BMAD) was calculated for each individual.ResultsDXA was evaluated in 234 subjects with DS (mean age 36.93 +/- 11.83 years, ranging from 20 to 69 years; 50.4% females). In the lumbar spine both mean BMD (DS 0.880 +/- 0.141 vs. NHANES 1.062 +/- 0.167, p < 0.001) and BMAD (DS 0.138 +/- 0.020 vs. NHANES 0.152 +/- 0.020, p < 0.001) were significantly lower in the DS sample than in the NAHNES cohort. The same trend was observed at the femoral neck in both BMD (DS 0.658 +/- 0.128 vs. NHANES 0.835 +/- 0.137, p < 0.001) and BMAD (DS 0.151 +/- 0.030 vs. NHANES 0.159 +/- 0.028, p < 0.001). Age was associated with lower femoral neck BMAD in both samples; importantly, this association was significantly stronger in the DS sample. In the lumbar spine region, no significant association between BMAD and age could be observed in both samples.ConclusionsAdults with DS have lower bone mineral density compared to the general population and they experience a steeper decline with age. Early screening programs are needed in DS population.
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| 4. |
- Girardi, Ivan, et al.
(författare)
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Constraining sterile neutrinos using reactor neutrino experiments
- 2014
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Ingår i: Journal of High Energy Physics (JHEP). - 1126-6708 .- 1029-8479. ; :8
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Tidskriftsartikel (refereegranskat)abstract
- Models of neutrino mixing involving one or more sterile neutrinos have resurrected their importance in the light of recent cosmological data. In this case, reactor antineutrino experiments offer an ideal place to look for signatures of sterile neutrinos due to their impact on neutrino flavor transitions. In this work, we show that the high-precision data of the Daya Bay experiment constrain the 3+1 neutrino scenario imposing upper bounds on the relevant active-sterile mixing angle sin(2) 2 theta(14) less than or similar to 0.06 at 3 sigma confidence level for the mass-squared difference Delta m(41)(2) in the range (10(-3), 10(-1)) eV(2). The latter bound can be improved by six years of running of the JUNO experiment, sin(2) 2 theta(14) less than or similar to 0.016, although in the smaller mass range Delta m(41)(2) is an element of(10(-4), 10(-3)) eV(2). We have also investigated the impact of sterile neutrinos on precision measurements of the standard neutrino oscillation parameters theta(13) and Delta m(31)(2) (at Daya Bay and JUNO), theta(12) and Delta m(21)(2) (at JUNO), and most importantly, the neutrino mass hierarchy (at JUNO). We find that, except for the obvious situation where Delta m(41)(2) similar to Delta m(31)(2), sterile states do not affect these measurements substantially.
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| 5. |
- Meloni, Davide, et al.
(författare)
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Effects of intermediate scales on renormalization group running of fermion observables in an SO(10) model
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- In the context of non-supersymmetric SO(10) models, we analyze the renormalization group equations for the fermions (including neutrinos) from the GUT energy scale down to the electroweak energy scale, explicitly taking into account the effects of an intermediate energy scal induced by a Pati-Salam gauge group. To determine the renomalization group running, we use a numerical minimization procedure based on a nested sampling algoritm that randomly generates the values of 19 model parameters at the GUT scale, evolves them, and finally constructs the values of te physical observables and compares them to the existing experimental data at the electroweak scale. We show that the evolved fermion masses and mixings present sizavle deviations from the values obtained without including the effects of the intermediate scale.
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| 6. |
- Meloni, Davide, et al.
(författare)
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Effects of intermediate scales on renormalization group running of fermion observables in an SO(10) model
- 2014
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Ingår i: Journal of High Energy Physics (JHEP). - 1126-6708 .- 1029-8479. ; :12, s. 052-
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Tidskriftsartikel (refereegranskat)abstract
- In the context of non-supersymmetric SO(10) models, we analyze the renormalization group equations for the fermions (including neutrinos) from the GUT energy scale down to the electroweak energy scale, explicitly taking into account the effects of an intermediate energy scale induced by a Pati-Salam gauge group. To determine the renormalization group running, we use a numerical minimization procedure based on a nested sampling algorithm that randomly generates the values of 19 model parameters at the GUT scale, evolves them, and finally constructs the values of the physical observables and compares them to the existing experimental data at the electroweak scale. We show that the evolved fermion masses and mixings present sizable deviations from the values obtained without including the effects of the intermediate scale.
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| 7. |
- Meloni, Davide, et al.
(författare)
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Exact and approximate formulas for neutrino mixing and oscillations with non-standard interactions
- 2009
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Ingår i: Journal of High Energy Physics (JHEP). - : IOP Publishing. - 1126-6708 .- 1029-8479. ; 2009:04, s. 033-
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Tidskriftsartikel (refereegranskat)abstract
- We present, both exactly and approximately, a complete set of mappings between the vacuum (or fundamental) leptonic mixing parameters and the effective ones in matter with non-standard neutrino interaction (NSI) effects included. Within the three-flavor neutrino framework and a constant matter density profile, a full set of sum rules is established, which enables us to reconstruct the moduli of the effective leptonic mixing matrix elements, in terms of the vacuum mixing parameters in order to reproduce the neutrino oscillation probabilities for future long-baseline experiments. Very compact, but quite accurate, approximate mappings are obtained based on series expansions in the neutrino mass hierarchy parameter eta equivalent to Delta m(21)(2)/Delta m(31)(2), the vacuum leptonic mixing parameter s(13) equivalent to sin theta(13), and the NSI parameters epsilon(alpha beta). A detailed numerical analysis about how the NSIs affect the smallest leptonic mixing angle theta(13), the deviation of the leptonic mixing angle theta(23) from its maximal mixing value, and the transition probabilities useful for future experiments are performed using our analytical results.
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| 8. |
- Meloni, Davide, et al.
(författare)
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Leptonic CP violation at neutrino telescopes
- 2012
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Ingår i: Physical Review D. - : American Physical Society. - 1550-7998 .- 1550-2368. ; 86:6, s. 067701-
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Tidskriftsartikel (refereegranskat)abstract
- With the advent of the recent measurements in neutrino physics, we investigate the role of high-energy neutrino flux ratios at neutrino telescopes for the possibility of determining the leptonic CP-violating phase delta and the underlying pattern of the leptonic mixing matrix. We find that the flux ratios show a dependence of O(10%) on the CP-violating phase, and for optimistic uncertainties on the flux ratios less than 10%, they can be used to distinguish between CP-conserving and CP-violating values of the phase at 2 sigma in a nonvanishing interval around the maximal value vertical bar delta vertical bar = pi/2.
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| 9. |
- Meloni, Davide, et al.
(författare)
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Neutrino flux ratios at neutrino telescopes : The role of uncertainties of neutrino mixing parameters and applications to neutrino decay
- 2007
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Ingår i: Physical Review D. - : The American Physical Society. - 1550-7998. ; 75:12, s. 125017-1-125017-12
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Tidskriftsartikel (refereegranskat)abstract
- In this paper, we derive simple and general perturbative formulas for the flavor flux ratios R-alpha beta=phi(nu alpha)/phi(nu beta) that could be measured at neutrino telescopes. We discuss in detail the role of the uncertainties of the neutrino mixing parameters showing that they have to be seriously taken into account in any realistic discussion about flavor measurements at neutrino telescopes. In addition, we analyze the impact of such uncertainties in telling the standard neutrino oscillation framework from scenarios involving, e.g., neutrino decay and we find that the ratio R-e mu is the most sensitive one to new physics effects beyond the standard model. We also compute the more realistic muon-to-shower ratio for a particular configuration of the IceCube experiment, observing that using this experimental quantity a clear separation between standard and nonstandard neutrino physics cannot be obtained.
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| 10. |
- Meloni, Davide, et al.
(författare)
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Non-standard interactions versus non-unitary lepton flavor mixing at a neutrino factory
- 2010
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Ingår i: Journal of High Energy Physics (JHEP). - : Springer-Verlag. - 1126-6708 .- 1029-8479. ; 2010:04, s. 041-
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Tidskriftsartikel (refereegranskat)abstract
- The impact of heavy mediators on neutrino oscillations is typically described by non-standard four-fermion interactions (NSIs) or non-unitarity (NU). We focus on leptonic dimension-six effective operators which do not produce charged lepton flavor violation. These operators lead to particular correlations among neutrino production, propagation, and detection non-standard effects. We point out that these NSIs and NU phenomenologically lead, in fact, to very similar effects for a neutrino factory, for completely different fundamental reasons. We discuss how the parameters and probabilities are related in this case, and compare the sensitivities. We demonstrate that the NSIs and NU can, in principle, be distinguished for large enough effects at the example of non-standard effects in the mu-tau-sector, which basically corresponds to differentiating between scalars and fermions as heavy mediators as leading order effect. However, we find that a near detector at superbeams could provide very synergistic information, since the correlation between source and matter NSIs is broken for hadronic neutrino production, while NU is a fundamental effect present at any experiment.
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