Higgs vacuum stability and inflationary dynamics after BICEP2 and PLANCK dust polarisation data

If the recent detection of $B-$mode polarization of the Cosmic Microwave Background by BICEP2 observations, withstand the test of time after the release of recent PLANCK dust polarisation data, then it would surprisingly put the inflationary scale near Grand Unification scale if one considers single-field inflationary models. On the other hand, Large Hadron Collider has observed the elusive Higgs particle whose presently observed mass can lead to electroweak vacuum instability at high scale $(\sim{\mathcal O}(10^{10})$ GeV). In this article, we seek for a simple particle physics model which can simultaneously keep the vacuum of the theory stable and yield high-scale inflation successfully. To serve our purpose, we extend the Standard Model of particle physics with a $U(1)_{B-L}$ gauged symmetry which spontaneously breaks down just above the inflationary scale. Such a scenario provides a constrained parameter space where both the issues of vacuum stability and high-scale inflation can be successfully accommodated. The threshold effect on the Higgs quartic coupling due to the presence of the heavy inflaton field plays an important role in keeping the electroweak vacuum stable. Furthermore, this scenario is also capable of reheating the universe at the end of inflation. Though the issues of Dark Matter and Dark Energy, which dominate the late-time evolution of our universe, cannot be addressed within this framework, this model successfully describes the early universe dynamics according to the Big Bang model.Comment: Title and text are modified to match the accepted version in JCAP. 22 pages, 3 figures, Latex fil

Classifying standard model extensions effectively with precision observables

Effective theories are well established theoretical frameworks to describe the effect of energetically widely separated UV models on observables at lower energy scales. Due to the complexity of the effective theory when taking all the Standard Model symmetries and degrees of freedom into account, tensioning the entire system in a completely agnostic way against experimental measurements results in constraints on the Wilson coefficients of the effective operators that either bears little information or challenge intrinsic assumptions imposed on the effective field theory framework. In general, a specific high-scale extension of the Standard Model only induces a subset of all possible operators. Thus, by investigating which operators are induced by different classes of the Standard Model extensions and comparing to which precision observables they contribute, we show that it is possible to obtain an improved understanding of which UV model is realised in nature. We present the tree + 1 -loop matching results for dimension-6 operators of 15 different BSM scenarios onto SMEFT, and also including, the specific model-based contributions to the observables. We argue that more observables and matching with higher theoretical precision will pave the way to distinguish the single scalar extensions of the SM signatures uniquely. We promote this approach to study new sets of observables in the context of current and near future experiments

CoDEx: Wilson coefficient calculator connecting SMEFT to UV theory

CoDEx is a Mathematica package that calculates the Wilson Coefficients (WCs) corresponding to effective operators up to mass dimension-6. Once the part of the Lagrangian involving single as well as multiple degenerate heavy fields, belonging to some Beyond Standard Model (BSM) theory, is given, the package can then integrate out propagators from the tree as well as 1-loop diagrams of that BSM theory. It then computes the associated WCs up to 1-loop level, for two different bases: "Warsaw" and "SILH". CoDEx requires only very basic information about the heavy field(s), e.g., Colour, Isospin, Hyper-charge, Mass, and Spin. The package first calculates the WCs at the high scale (mass of the heavy field(s)). We then have an option to perform the renormalisation group evolutions (RGEs) of these operators in "Warsaw" basis, a complete one (unlike "SILH"), using the anomalous dimension matrix. Thus, one can get all effective operators at the electro-weak scale, generated from any such BSM theory, containing heavy fields of spin: 0, 1/2, and 1. We have provided many example models (both here and in the package-documentation) that more or less encompass different choices of heavy fields and interactions. Relying on the status of the present day precision data, we restrict ourselves up to dimension-6 effective operators. This will be generalised for any dimensional operators in a later version. Site: https://effexteam.github.io/CoDExComment: 25 pages, 1 figure, corrections and citations adde

Analyzing the antimicrobial efficacy of the economically important tree Knema linifolia (Roxb.) Warb

Knema linifolia is widely used for fuel wood, fodder and healthcare purposes. This plant treats various diseases in different parts of India, including Assam, Meghalaya, Alipurduar and Darjeeling districts of West Bengal. This study was carried out to determine the bactericidal properties of various parts of K. linifolia aqueous extract. The aqueous extract of the leaves, bark, stem and plant sap were tested against Escherichia coli (gram-negative bacteria) & Staphylococcus aureus (gram-positive bacteria). Among the tested extracts, both the leaf and bark extracts were found to have high bactericidal potential and can kill more than 60% of both bacterial strains with a concentration of 300µg/mL through an agar diffusion test. The MIC (Minimum Inhibitory Concentration) values for the leaf and bark extracts were recorded at ≤1000µg/mL & ≤500µg/mL, respectively. It has also been found that both the bark and leaf extracts contain high tannins, which might be essential for the antibacterial properties of Knema sp. There is currently a lack of proper documentation on using K. linifolia, which makes it challenging to conduct clinical or commercial research to support new uses in modern phototherapy. This study aims to fill this gap and provide significant information that could lead to changes in modern medicine