Hunting BFKL in semi-hard reactions at the LHC

The agreement between calculations inspired by the resummation of energy logarithms, known as BFKL approach, and experimental data in the semi-hard sector of QCD has become manifest after a wealthy series of phenomenological analyses. However, the contingency that the same data could be concurrently portrayed at the hand of fixed-order, DGLAP-based calculations, has been pointed out recently, but not yet punctually addressed. Taking advantage of the richness of configurations gained by combining the acceptances of CMS and CASTOR detectors, we give results in the full next-to-leading logarithmic approximation of cross sections, azimuthal correlations and azimuthal distributions for three distinct semi-hard processes, each of them featuring a peculiar final-state exclusiveness. Then, making use of disjoint intervals for the transverse momenta of the emitted objects, i.e. $$\kappa $$ κ -windows, we clearly highlight how high-energy resummed and fixed-order driven predictions for semi-hard sensitive observables can be decisively discriminated in the kinematic ranges typical of current and forthcoming analyses at the LHC. The scale-optimization issue is also introduced and explored, while the uncertainty coming from the use of different PDF and FF set is deservedly handled. Finally, a brief overview of , a numerical tool recently developed, suited for the computation of inclusive semi-hard reactions is provided.

A Hybrid Radix-4 and Approximate Logarithmic Multiplier for Energy Efficient Image Processing

Multiplication is an essential image processing operation commonly implemented in hardware DSP cores. To improve DSP cores’ area, speed, or energy efficiency, we can approximate multiplication. We present an approximate multiplier that generates two partial products using hybrid radix-4 and logarithmic encoding of the input operands. It uses the exact radix-4 encoding to generate the partial product from the three most significant bits and the logarithmic approximation with mantissa trimming to approximate the partial product from the remaining least-significant bits. The proposed multiplier fills the gap between highly accurate approximate non-logarithmic multipliers with a complex design and less accurate approximate logarithmic multipliers with a more straightforward design. We evaluated the multiplier’s efficiency in terms of error, energy (power-delay-product) and area utilisation using NanGate 45 nm. The experimental results show that the proposed multiplier exhibits good area utilisation and energy consumption and behaves well in image processing applications.

Exact summation of leading logs around $$ T\overline{T} $$ deformation of O(N + 1)-symmetric 2D QFTs

We consider a general (beyond $$ T\overline{T} $$ T T ¯ ) deformation of the 2D O(N + 1) σ-model by the irrelevant dimension-four operators. The theory deformed in this most general way is not integrable, and the S-matrix loses its factorization properties. We perform the all-order summation of the leading infrared logs for the 2 → 2 scattering amplitude and provide the exact result for the 2 → 2 S-matrix in the leading logarithmic approximation. These results can provide us with new insights into the properties of the theories deformed by irrelevant operators more general than the $$ T\overline{T} $$ T T ¯ deformation.

Rise of the DIS structure function FL at small x caused by double-logarithmic corrections

We present calculation of FL in the double-logarithmic approximation (DLA) and demonstrate that the synergic effect of the factor 1/x from the $$ {\alpha}_s^2 $$ α s 2 -order and the steep x-dependence of the totally resummed double logarithmic contributions of higher orders ensures the power-like rise of FL at small x and arbitrary Q2.

Erratum to: Light quark mediated Higgs boson threshold production in the next-to-leading logarithmic approximation

In the paper a NLL contribution of the gluon vertex correction figure 4(c) has been omitted.

Estimating the Intensity of Hurricanes from Historical Radar Data Using the Hyperbolic-logarithmic approximation of Spiral Rainbands

To increase the amount of information on the intensities of tropical cyclones (TC) used in climate research, the possibility of additional estimates of the intensity of a TC by exploring historical data of conventional (non-Doppler) airborne and coastal radars is considered. Based on the hyperbolic-logarithmic spiral (HLS) model of the streamline in the TC, an assessment of the maximum wind speed in hurricanes Cleo (1958), Carolina (1975) and Alicia (1983) was made. Literature sources containing radar signatures of spiral cloud-rain bands (SCRBs) of these hurricanes and the corresponding results of synchronous aircraft soundings were used. The HLS-approximation of the radar signature of the SCRB consisted of determining the “expected” (mean) spiral of a set of HLSs “fitted” into a pattern of the signature. The maximum wind speed was determined from coefficients of the mean HLS. The estimates obtained were in satisfactory agreement with in situ aircraft measurements. The considered examples manifest the possibility of applying the HLS-approximation to determine the intensity of hurricanes by using the historical radar data with satisfactory accuracy.