2,372 research outputs found
S3 as a flavour symmetry for quarks and leptons after the Daya Bay result on \theta 13
We present a model based on the flavour group S3 X Z3 X Z6 to explain the
main features of fermion masses and mixing. In particular, in the neutrino
sector the breaking of the S3 symmetry is responsible for a naturally small
r=\Delta m^2_sol/\Delta m^2_atm and suitable next-to-leading order corrections
bring \theta 13 at the level of ~ 0.13, fully compatible with the recent Daya
Bay result. In the quark sector, the model accommodates the different mass
hierarchies in the up and down quark sectors as well as the Cabibbo angle and
Vcb (or Vub, depending on the charge assignment of the right-handed b-quark) in
the correct range.Comment: 15 pages, 3 figure
The Golden Ratio Prediction for the Solar Angle from a Natural Model with A5 Flavour Symmetry
We formulate a consistent model predicting, in the leading order
approximation, maximal atmospheric mixing angle, vanishing reactor angle and
tan {\theta}_12 = 1/{\phi} where {\phi} is the Golden Ratio. The model is based
on the flavour symmetry A5 \times Z5 \times Z3, spontaneously broken by a set
of flavon fields. By minimizing the scalar potential of the theory up to the
next-to-leading order in the symmetry breaking parameter, we demonstrate that
this mixing pattern is naturally achieved in a finite portion of the parameter
space, through the vacuum alignment of the flavon fields. The leading order
approximation is stable against higher-order corrections. We also compare our
construction to other models based on discrete symmetry groups.Comment: 28 pages, 2 figures. Minor changes, references added. Corrected typos
in Appendix A. Version appeared on JHE
Hadronic production of bottom-squark pairs with electroweak contributions
We present the complete computation of the tree-level and the next-to-leading
order electroweak contributions to bottom-squark pair production at the LHC.
The computation is performed within the minimal supersymmetric extension of the
Standard Model. We discuss the numerical impact of these contributions in
several supersymmetric scenarios.Comment: 33 pages, v2: preprint numbers correcte
You turn me cold: evidence for temperature contagion
Introduction
During social interactions, our own physiological responses influence those of others. Synchronization of physiological (and behavioural) responses can facilitate emotional understanding and group coherence through inter-subjectivity. Here we investigate if observing cues indicating a change in another's body temperature results in a corresponding temperature change in the observer.
Methods
Thirty-six healthy participants (age; 22.9±3.1 yrs) each observed, then rated, eight purpose-made videos (3 min duration) that depicted actors with either their right or left hand in visibly warm (warm videos) or cold water (cold videos). Four control videos with the actors' hand in front of the water were also shown. Temperature of participant observers' right and left hands was concurrently measured using a thermistor within a Wheatstone bridge with a theoretical temperature sensitivity of <0.0001°C. Temperature data were analysed in a repeated measures ANOVA (temperature × actor's hand × observer's hand).
Results
Participants rated the videos showing hands immersed in cold water as being significantly cooler than hands immersed in warm water, F(1,34) = 256.67, p0.1). There was however no evidence of left-right mirroring of these temperature effects p>0.1). Sensitivity to temperature contagion was also predicted by inter-individual differences in self-report empathy.
Conclusions
We illustrate physiological contagion of temperature in healthy individuals, suggesting that empathetic understanding for primary low-level physiological challenges (as well as more complex emotions) are grounded in somatic simulation
A consumer segmentation proposal in the wine sector.
O mercado de vinhos apresenta perspectiva de crescimento no Brasil para os pr?ximos anos. Contudo, s?o poucas as pesquisas acad?micas publicadas no pa?s que abordam a segmenta??o dos consumidores deste setor. Neste contexto, este estudo teve como objetivo identificar diferentes segmentos de consumidores no mercado de vinhos com base no comportamento apresentado durante o processo de decis?o de compra. Como m?todo de pesquisa, realizou-se um levantamento de campo. A amostra do estudo foi composta por 370 habitantes das cidades de Mariana e Ouro Preto, ambas localizadas no Estado de Minas Gerais. Para an?lise dos dados, efetuou-se uma An?lise de Clusters, a partir da qual foram identificados dois segmentos de consumidores: os eventuais e os apaixonados por vinho. Os consumidores eventuais compram por impulso e tem o pre?o como principal crit?rio de escolha. J? os consumidores apaixonados por vinhos compram de forma planejada e frequente, considerando v?rios crit?rios em sua escolha, pois se tornou um h?bito o consumo desse produto. Para estudos futuros, sugere-se que a metodologia de pesquisa utilizada seja aplicada em amostras de outras regi?es do pa?s. Adicionalmente, sugere-se que sejam utilizadas tamb?m outras bases de segmenta??o para avan?ar na identifica??o dos diferentes grupos de consumidores de vinhos no Brasil.The wine market presents growth prospects in Brazil for the coming years. Despite this, there is few published academic research in the country that explores consumer segmentation in this sector. In this context, this study aimed to identify different consumer segments in the wine market based on the behavior presented during the purchase decision process. To reach this objective, a survey was conducted using a sample consisted of 370 inhabitants of the cities of Mariana and Ouro Preto, both located in Minas Gerais state, Brazil. To analyze the collected data, a Clusters Analysis was carried out, through which it was possible to identify two segments of consumers: the occasional one and the enthusiastic one. Occasional consumers buy on impulse and have the price as the main criterion of choice. On the other hand, enthusiastic consumers buy frequently and in a planned way, considering several criteria in their choice, because wine consumption has become a habit. For future studies, it is suggested that the used research methodology is applied to samples from other regions of the country. In addition, it is suggested that other segmentation bases are used to contribute to the identification of different groups of wine consumers in Brazil
Ultraviolet Completion of Flavour Models
Effective Flavour Models do not address questions related to the nature of
the fundamental renormalisable theory at high energies. We study the
ultraviolet completion of Flavour Models, which in general has the advantage of
improving the predictivity of the effective models. In order to illustrate the
important features we provide minimal completions for two known A4 models. We
discuss the phenomenological implications of the explicit completions, such as
lepton flavour violating contributions that arise through the exchange of
messenger fields.Comment: 18 pages, 8 figure
Decaying Dark Matter in the Supersymmetric Standard Model with Freeze-in and Seesaw mechanims
Inspired by the decaying dark matter (DM) which can explain cosmic ray
anomalies naturally, we consider the supersymmetric Standard Model with three
right-handed neutrinos (RHNs) and R-parity, and introduce a TeV-scale DM sector
with two fields \phi_{1,2} and a discrete symmetry. The DM sector only
interacts with the RHNs via a very heavy field exchange and then we can explain
the cosmic ray anomalies. With the second right-handed neutrino N_2 dominant
seesaw mechanism at the low scale around 10^4 GeV, we show that \phi_{1,2} can
obtain the vacuum expectation values around the TeV scale, and then the
lightest state from \phi_{1,2} is the decay DM with lifetime around \sim
10^{26}s. In particular, the DM very long lifetime is related to the tiny
neutrino masses, and the dominant DM decay channels to \mu and \tau are related
to the approximate \mu-\tau symmetry. Furthermore, the correct DM relic density
can be obtained via the freeze-in mechanism, the small-scale problem for power
spectrum can be solved due to the decays of the R-parity odd meta-stable states
in the DM sector, and the baryon asymmetry can be generated via the soft
leptogensis.Comment: 24 pages,3 figure
Minimal flavour violation extensions of the seesaw
We analyze the most natural formulations of the minimal lepton flavour
violation hypothesis compatible with a type-I seesaw structure with three heavy
singlet neutrinos N, and satisfying the requirement of being predictive, in the
sense that all LFV effects can be expressed in terms of low energy observables.
We find a new interesting realization based on the flavour group (being and respectively the SU(2) singlet and
doublet leptons). An intriguing feature of this realization is that, in the
normal hierarchy scenario for neutrino masses, it allows for sizeable
enhancements of transitions with respect to LFV processes involving
the lepton. We also discuss how the symmetries of the type-I seesaw
allow for a strong suppression of the N mass scale with respect to the scale of
lepton number breaking, without implying a similar suppression for possible
mechanisms of N productionComment: 14 pages, 6 figure
Large-Theta(13) Perturbation Theory of Neutrino Oscillation for Long-Baseline Experiments
The Cervera et al. formula, the best known approximate formula of neutrino
oscillation probability for long-baseline experiments, can be regarded as a
second-order perturbative formula with small expansion parameter epsilon \equiv
Delta m^2_{21} / Delta m^2_{31} \simeq 0.03 under the assumption s_{13} \simeq
epsilon. If theta_{13} is large, as suggested by a candidate nu_{e} event at
T2K as well as the recent global analyses, higher order corrections of s_{13}
to the formula would be needed for better accuracy. We compute the corrections
systematically by formulating a perturbative framework by taking theta_{13} as
s_{13} \sim \sqrt{epsilon} \simeq 0.18, which guarantees its validity in a wide
range of theta_{13} below the Chooz limit. We show on general ground that the
correction terms must be of order epsilon^2. Yet, they nicely fill the mismatch
between the approximate and the exact formulas at low energies and relatively
long baselines. General theorems are derived which serve for better
understanding of delta-dependence of the oscillation probability. Some
interesting implications of the large theta_{13} hypothesis are discussed.Comment: Fig.2 added, 23 pages. Matches to the published versio
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