We perform a comprehensive analysis of scalar contributions in b→cτν transitions including the latest measurements of R(D(⁎)), the q2 differential distributions in B→D(⁎)τν, the τ polarization ...asymmetry for B→D⁎τν, and the bound derived from the total width of the Bc meson. We find that scalar contributions with the simultaneous presence of both left- and right-handed couplings to quarks can explain the available data, specifically R(D(⁎)) together with the measured differential distributions. However, the constraints from the total Bc width present a slight tension with the current data on B→D⁎τν in this scenario, preferring smaller values for R(D⁎). We discuss possibilities to disentangle scalar new physics from other new-physics scenarios like the presence of only a left-handed vector current, via additional observables in B→D(⁎)τν decays or additional decay modes like the baryonic Λb→Λcτν and the inclusive B→Xcτν decays. We also analyze scalar contributions in b→uτν transitions, including the latest measurements of B→τν, providing predictions for Λb→pτν and B→πτν decays. The potential complementarity between the b→u and b→c sectors is finally investigated once assumptions about the flavour structure of the underlying theory are made.
We study the generic features of minimal gauge extensions of the Standard Model in view of recent hints of lepton-flavor non-universality in semi-leptonic b→sℓ+ℓ− and b→cℓν decays. We classify the ...possible models according to the symmetry-breaking pattern and the source of flavor non-universality. We find that in viable models the SU(2)L factor is embedded non-trivially in the extended gauge group, and that gauge couplings should be universal, hinting to the presence of new degrees of freedom sourcing non-universality. Finally, we provide an explicit model that can explain the B-decay anomalies in a coherent way and confront it with the relevant phenomenological constraints.
We present DsixTools, a Mathematica package for the handling of the dimension-six standard model effective field theory. Among other features, DsixTools allows the user to perform the full one-loop ...renormalization group evolution of the Wilson coefficients in the Warsaw basis. This is achieved thanks to the SMEFTrunner module, which implements the full one-loop anomalous dimension matrix previously derived in the literature. In addition, DsixTools also contains modules devoted to the matching to the
Δ
B
=
Δ
S
=
1
,
2
and
Δ
B
=
Δ
C
=
1
operators of the Weak Effective Theory at the electroweak scale, and their QCD and QED Renormalization group evolution below the electroweak scale.
LHC constraints on two-Higgs doublet models Celis, Alejandro; Ilisie, Victor; Pich, Antonio
The journal of high energy physics,
07/2013, Volume:
2013, Issue:
7
Journal Article
Peer reviewed
Open access
A
bstract
A new Higgs-like boson with mass around 126 GeV has recently been discovered at the LHC. The available data on this new particle is analyzed within the context of two-Higgs doublet models ...without tree-level flavour-changing neutral currents. Keeping the generic Yukawa structure of the Aligned Two-Higgs Doublet Model framework, we study the implications of the LHC data on the allowed scalar spectrum. We analyze both the CP-violating and CP-conserving cases, and a few particular limits with a reduced number of free parameters, such as the usual models based on discrete
symmetries.
A
bstract
We study the patterns of flavour violation in renormalisable extensions of the Standard Model (SM) that contain vector-like quarks (VLQs) in a single complex representation of either the SM ...gauge group G
SM
or G
SM
′
≡ G
SM
⊗ U(1)L
μ
− L
τ
.
We first decouple VLQs in the
M
= (1 − 10) TeV range and then at the electroweak scale also
Z, Z
′
gauge bosons and additional scalars to study the phenomenology. The results depend on the relative size of
Z
- and
Z
′
-induced flavour-changing neutral currents, as well as the size of |Δ
F
| = 2 contributions including the effects of renormalisation group Yukawa evolution from
M
to the electroweak scale that turn out to be very important for models with right-handed currents through the generation of left-right operators. In addition to rare decays like
P
→
ℓ
ℓ
¯
,
P
→
P
′
ℓ
ℓ
¯
,
P
→
P
′
ν
ν
¯
with
P
=
K, B
s
, B
d
and |Δ
F
| = 2 observables we analyze the ratio
ε
′
/ε
which appears in the SM to be significantly below the data. We study patterns and correlations between these observables which taken together should in the future allow for differentiating between VLQ models. In particular the patterns in models with left-handed and right-handed currents are markedly different from each other. Among the highlights are large
Z
-mediated new physics effects in Kaon observables in some of the models and significant effects in
B
s,d
-observables.
ε
′
/ε
can easily be made consistent with the data, implying then uniquely the suppression of
K
L
→
π
0
ν
ν
¯
. Significant enhancements of
B
r
K
+
→
π
+
ν
ν
¯
are still possible. We point out that the combination of NP effects to |Δ
F
| = 2 and |Δ
F
| = 1 observables in a given meson system generally allows to determine the masses of VLQs in a given representation independently of the size of VLQ couplings.
We analyze the possibility to accommodate current b→sℓ+ℓ− anomalies with TeV-scale mediators that couple to right-handed top quarks and muons, contributing to b→sℓ+ℓ− at the one-loop level. We use ...the Standard Model Effective Field Theory (SMEFT) framework but also look at specific scenarios by taking into account all possible irreducible representations of the Lorentz and Standard Model gauge group for the mediators. From a global fit of b→sℓ+ℓ− data and LEP-I observables we find that the Wilson coefficients of two SMEFT operators: Oℓu=(ℓ¯LμγαℓLμ)(t¯RγαtR) and Oeu=(μ¯RγαμR)(t¯RγαtR) need to satisfy Ceu∼Cℓu. New physics enters then in b→sℓ+ℓ− mainly through the operator O9=(s¯γμPLb)(ℓ¯γμℓ) of the Weak Effective Theory. After discussing all possible mediators, we concentrate on two scenarios: A vector boson in the irreducible representation Zμ′∼(1,1,0) of the Standard Model gauge group with vectorial coupling to muons, and a combination of two leptoquarks: the scalar R2∼(3,2,7/6) and the vector U˜1μ∼(3,1,5/3). We derive LHC constraints by recasting di-muon resonance, pp→tt¯tt¯ and SUSY searches. Additionally, we analyze the prospects for discovering these mediators during the high-luminosity phase of the LHC.
A
bstract
We discuss Yukawa-enhanced contributions from
Z
-mediated new physics to down-type quark Δ
F
= 2 processes in the framework of the standard model gauge-invariant effective theory (SMEFT). ...Besides the renormalization group (RG) mixing of the
Z
-mediating
ψ
2
H
2
D
operators into Δ
F
= 2 operators, we include at the electroweak scale one-loop (NLO) matching corrections consistently, necessary for the removal of the matching scale dependence. We point out that the right-handed
Z
-mediated interactions generate through Yukawa RG mixing Δ
F
= 2 left-right operators, which are further enhanced through QCD RG effects and chirally enhanced hadronic matrix elements. We investigate the impact of these new effects on the known correlations between Δ
F
= 2 and Δ
F
= 1 transitions in the SMEFT framework and point out qualitative differences to previous parameterizations of
Z
-mediated new physics that arise for the left-handed case. We illustrate how specific models fit into our model-independent framework by using four models with vector-like quarks. We carry out model-independent analyses of scenarios with purely left-handed and purely right-handed new-physics
Z
couplings for each of the three sectors
s
→
d
,
b
→
s
and
b
→
d
. Specifically we discuss the correlations between
ε
′
/ε
,
ε
K
,
K
L
→
μ
+
μ
−
K
+
→
π
+
ν
ν
¯
and
K
L
→
π
0
ν
ν
¯
in the Kaon sector, and
ϕ
s
,
B
s
→
μ
+
μ
−
and
B
→
K
(*)
(
μ
+
μ
−
,
ν
ν
¯
) in the
b
→
s
sector and
B
d
→
μ
+
μ
−
in the
b
→
d
sector.
We derive the necessary conditions to build a class of invisible axion models with Flavor Changing Neutral Currents at tree-level controlled by the fermion mixing matrices and present an explicit ...model implementation. A horizontal Peccei–Quinn symmetry provides a solution to the strong CP problem via the Peccei–Quinn mechanism and predicts a cold dark mater candidate, the invisible axion or familon. The smallness of active neutrino masses can be explained via a type I seesaw mechanism, providing a dynamical origin for the heavy seesaw scale. The possibility to avoid the domain wall problem stands as one of the most interesting features of the type of models considered. Experimental limits relying on the axion–photon coupling, astrophysical considerations and familon searches in rare kaon and muon decays are discussed.
We discuss the possibility of having a non-minimal scalar sector at the weak scale within the framework of invisible axion models. To frame our discussion we consider an extension of the ...Dine–Fischler–Srednicki–Zhitnitsky invisible axion model with two additional Higgs doublets blind under the Peccei–Quinn symmetry. Due to mixing effects among the scalar fields, it is possible to obtain a rich scalar sector at the weak scale in certain decoupling limits of the theory. In particular, this framework provides an ultraviolet completion of the so-called aligned two-Higgs-doublet model and solves the strong CP problem. The axion properties and the smallness of active neutrino masses are also discussed.
La aglomeracion de empresas culturales/creativas y establecimientos de consumo especializado en distritos urbanos marcados por un proceso de rapida transformacion urbana se ha identificado como ...distritos creativos y se asume que son clusters economicos, en el sentido en que forman un sistema aglomerado de empresas especializadas y su correspondiente mercado laboral. Para esta investigacion, estos distritos son una parte visible e idealizada de un cluster economico mas grande que opera en una escala metropolitana y que incluye zonas, empresas y trabajos diversos. Se inicia este texto discutiendo la problematica conceptual y metodologica de llevar el concepto de cluster economico a la escala geografica intraurbana. Con ello, se confronta la idea de distritos creativos como espacios economicos funcionales y separables del resto de la economia metropolitana donde se ubican. Posteriormente, se aplican los metodos que comunmente se utilizan en los estudios ur-banos sobre industrias creativas para identificar posibles distritos creativos en la Ciudad de Mexico. Los distritos identificados son contrastados en sus estructuras y especializaciones economicas para determinar si hay indicios de que, efectivamente, sean espacios economicos funcionales diferenciables del resto de la zona metropolitana. Se concluye argumentando que los datos encontrados sustentan la existencia de un solo cluster economico metropolitano y no de pequenos clusters.//The agglomeration of cultural / creative businesses and establishments specialized consumption in urban districts marked by a process of rapid urban transformation has been identified as 'creative districts' and are assumed to be economic clusters, in the sense that they form a cluster system companies specialized and corresponding labor market. For this research, these districts are a visible and idealized part of a larger economic cluster operating on a metropolitan scale and includes areas, enterprises and jobs. This text begins discussing the conceptual and methodological problems of bringing the concept of economic cluster to intraurban geographical scale. Thus the idea of 'creative districts' as functional economic areas and separable from the rest of the metropolitan economy is confronted where they are located. Subsequently, the methods commonly used in urban studies on creative industries to identify possible creative districts in Mexico City apply. The identified districts are contrasted in their economic structures and specializations to determine if there are indications that indeed are differentiable functional economic areas from the rest of the metropolitan area. It concludes by arguing that the data found support the existence of a single metropolitan economic cluster and non-small clusters. http://www.redalyc.org/html/357/35744556008/index.html Reprinted by permission of the Centro Interdisciplinario de Estudios Regionales
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