Resummed prediction for Higgs boson production through bbˉb\bar{b} annihilation at N3^3LL

We present an accurate theoretical prediction for the production of Higgs boson through bottom quark annihilation at the LHC up to next-to-next-to-next-to leading order (N$^3$LO) plus next-to-next-to-next-to-leading logarithmic (N$^3$LL) accuracy. We determine the third order perturbative Quantum Chromodynamics (QCD) correction to the process dependent constant in the resummed expression using the three loop bottom quark form factor and third order quark soft distribution function. Thanks to the recent computation of N$^3$LO corrections to this production cross-section from all the partonic channels, an accurate matching can be obtained for a consistent predictions at N$^3$LO+N$^3$LL accuracy in QCD. We have studied in detail the impact of resummed threshold contributions to inclusive cross-sections at various centre-of-mass energies and also discussed their sensitivity to renormalization and factorization scales at next-to-next-to leading order (NNLO) matched with next-to-next-to leading logarithm (NNLL). At N$^3$LO+N$^3$LL, we predict the cross-section for different centre-of-mass energies using the recently available results in \cite{Duhr:2019kwi} as well as study the renormalization scale dependence at the same order.Comment: 19 pages, 4 figures, 2 table

On next to soft corrections to Drell-Yan and Higgs Boson productions

We present a framework that resums threshold enhanced large logarithms to all orders in perturbation theory for the production of a pair of leptons in Drell-Yan process and of Higgs boson in gluon fusion as well as in bottom quark annihilation. We restrict ourselves to contributions from diagonal partonic channels. These logarithms include the distributions $((1-z)^{-1} \ln^i(1-z))_+$ resulting from soft plus virtual (SV) and the logarithms $\ln^i(1-z)$ from next-to-SV (NSV) contributions. We use collinear factorisation and renormalisation group invariance to achieve this. The former allows one to define a Soft-Collinear (SC) function which encapsulates soft and collinear dynamics of the perturbative results to all orders in strong coupling constant. The logarithmic structure of these results are governed by universal infrared anomalous dimensions and process dependent functions of Sudakov differential equation that the SC satisfies. The solution to the differential equation is obtained by proposing an all-order ansatz in dimensional regularisation, owing to several state-of-the-art perturbative results available to third order. The $z$ space solutions thus obtained provide an integral representation to sum up large logarithms originating from both soft and collinear configurations, conveniently in Mellin $N$ space. We show that in $N$ space, tower of logarithms $a_s^n/N^\alpha \ln^{2n-\alpha} (N), a_s^n/N^\alpha \ln^{2n-1-\alpha}(N) \cdots$ etc for $\alpha =0,1$ are summed to all orders in $a_s$.Comment: 55 Pages, 3 Table

Next-to-soft Virtual Resummation for QCD Observables

We present a framework that resums threshold-enhanced logarithms, originating from soft-virtual and next-to-soft virtual (NSV) contributions in colour-singlet productions, to all orders in perturbation theory. The numerical impacts for these resummed predictions are discussed for the inclusive Drell–Yan di-lepton process up to next-to-next-to-leading logarithmic accuracy, restricting to only diagonal partonic channels

Resummed Higgs boson cross section at next-to SV to NNLO+NNLL‾ \rm NNLO + \rm \overline {NNLL}

We present the resummed predictions for inclusive cross section for the production of Higgs boson at next-to-next-to leading logarithmic ($\rm \overline {NNLL}$) accuracy taking into account both soft-virtual ($\rm SV$) and next-to SV ($\rm NSV$) threshold logarithms. We derive the $N$-dependent coefficients and the $N$-independent constants in Mellin-$N$ space for our study. Using the minimal prescription we perform the inverse Mellin transformation and match it with the corresponding fixed order results. We report in detail the numerical impact of $N$-independent part of resummed result and explore the ambiguity involved in exponentiating them. By studying the K factors at different logarithmic accuracy, we find that the perturbative expansion shows better convergence improving the reliability of the prediction at $\rm NNLO + \overline{NNLL}$ accuracy. For instance, the cross-section at $\rm NNLO + \overline{NNLL}$ accuracy reduces by $3.15\%$ as compared to the $\rm NNLO$ result for the central scale $\mu_R = \mu_F = m_H/2$ at 13 TeV LHC. We also observe that the resummed $\rm SV + NSV$ result improves the renormalisation scale uncertainty at every order in perturbation theory. The uncertainty from the renormalisation scale $\mu_R$ ranges between $(+8.85\% ,-10.12\%)$ at $\rm NNLO$ whereas it goes down to $(+6.54\% , - 8.32\%)$ at $\rm NNLO + \overline{NNLL}$ accuracy. However, the factorisation scale uncertainty is worsened by the inclusion of these NSV logarithms hinting the importance of resummation beyond $\rm NSV$ terms. We also present our predictions for $\rm SV + NSV$ resummed result at different collider energies.Comment: 51 pages, 6 Figure

Expanded stability of layered SnSe-PbSe alloys and evidence of displacive phase transformation from rocksalt in heteroepitaxial thin films

Bulk PbSnSe has a two-phase region or miscibility gap as the crystal changes from a Van der Waals-bonded orthorhombic 2D layered structure in SnSe-rich compositions to the related 3D-bonded rocksalt structure in PbSe-rich compositions with large contrast in the electrical, optical, and thermal properties across this transition. With an aim to understand and harness this transition in thin films devices, we epitaxially integrate PbSnSe on GaAs by molecular beam epitaxy using an in-situ PbSe surface treatment and show a significantly reduced two-phase region by stabilizing the Pnma layered structure out to Pb$_{0.45}$Sn$_{0.55}$Se, beyond the bulk-limit of Pb$_{0.25}$Sn$_{0.75}$Se. Pushing further, we directly access metastable two-phase epitaxial films of layered and rocksalt grains that are nearly identical in composition around Pb$_{0.5}$Sn$_{0.5}$Se and entirely circumvent the miscibility gap. We present microstructural evidence for an incomplete displacive transformation from rocksalt to layered structure in these films that we speculate occurs during the sample cool down to room temperature after synthesis. In-situ x-ray diffraction measurement of an as-grown Pb$_{0.56}$Sn$_{0.44}$Se rocksalt film under cryogenic cooling reproduces the key attributes of this transition and validates our hypothesis. Notably, we find well-defined orientation relationships between the phases forming in the process and unconventional strain-relief mechanisms involved in the crystal structure transformation by transmission electron microscopy. Overall, our work adds a scalable thin film integration route to harnessing metastable layered compositions as well as the dramatic contrast in material properties in PbSnSe across a potentially ultrafast structural transition.Comment: 26 pages, 10 figure

Evaluation of Boerhavia diffusa and Eichhornia crassipes plant extracts in vitro as potential antifungal agents against human pathogenic fungi Candida albician and Candida tropicalis : A comparative study

Plant extracts are used to make herbal remedies with no side effects and little expense. During the COVID-19 pandemic, fungal species responsible for mucormycosis were found resistant to a variety of antifungals, including flucytosine, ketoconazole, fluconazole, voriconazole, itraconazole and echinocandins, due to their variable susceptibility. Amphotericin B is widely used as an antifungal agent due to its high inhibition capacity against various fungi. The present study aimed to compare the antifungal potential of Amphotericin B and herbal extract in vitro. The experiment was designed to measure zones of inhibition with the help of well-diffusion method. Four solvents, viz. methanol, chloroform, hexane and distilled water, were used to extract plant extract. The efficiency of plant extracts was found to be low compared to Amphotericin B (1.4mm). Chloroform extract of Boerhavia diffusa was found antifungal against Candida albician and C. tropicalis (0.45mm). Methanol and hexane extract of Eichhornia crassipes showed higher antifungal activity (1.35mm) and (1.75mm), respectively. The plant extracts also showed significant antifungal activity against C. tropicalis, revealing its potential to be used as a natural antifungal agent (1.1mm). Additionally, the findings showed that the chloroform and methanol extracts of B. diffusa and E. crassipes were also efficient against C. albician and C. tropicalis. The findings provide important insights about using plant extracts as a potential alternative to conventional antifungal agents.