Precision predictions for electroweak superpartner production at hadron colliders with Resummino

Abstract: We describe the Resummino package, a C++ and Fortran program dedicated to precision calculations in the framework of gaugino and slepton pair production at hadron colliders. This code allows to calculate transverse-momentum and invariant-mass distributions as well as total cross sections by combining the next-to-leading order predictions obtained by means of perturbative QCD with the resummation of the large logarithmic contributions arising in the small transverse-momentum region and close to the production threshold. The results computed in this way benefit from reduced theoretical uncertainties, compared to a pure next-to-leading order approach as currently employed in the experimental analyses searching for sleptons and gauginos at hadron colliders. This is illustrated by using of Resummino in the context of a typical supersymmetric benchmark point dedicated to superpartner searches at the Large Hadron Collider.

• The paper presents an integrated computational package combining next-to-leading order QCD and advanced resummation formalisms to reduce theoretical uncertainties in electroweak superpartner production.
• The methodology employs threshold, transverse-momentum, and joint resummation techniques, enabling accurate predictions for gaugino and slepton pair production at the LHC.
• The implementation in C++ and Fortran, with compatibility for LHAPDF and SLHA, provides a robust tool for supersymmetric searches in high-energy collider experiments.

Overview of the Paper on Precision Predictions for Electroweak Superpartner Production at Hadron Colliders

The paper "Precision predictions for electroweak superpartner production at hadron colliders" offers a comprehensive examination of a computational package designed for precision calculations in supersymmetric particle production. This package is specifically tailored to address the production of gaugino and slepton pairs at hadron colliders, with particular adaptability for scenarios encountered at the Large Hadron Collider (LHC). In focusing on supersymmetric processes, the authors advance the accuracy of cross-section predictions through the integration of next-to-leading order (NLO) perturbative QCD computations with resummation techniques. This confluence yields predictions characterized by minimized theoretical uncertainties, outperforming purely fixed-order approaches.

Methodological Insights

The core of the effort centers around improving the precision of theoretical predictions by deploying advanced resummation formalisms. These formalisms effectively address the large logarithmic corrections often seen near the production threshold or in small transverse momentum ($p_T$) domains that traditional NLO calculations struggle with. The paper provides a methodical breakdown of different resummation regimes:

1. Threshold Resummation: Concentrated on scenarios where the invariant mass of produced particles is near the collider's energy, this resummation framework captures contributions from soft gluon emission. The methodology resums logarithms of momentum fractions up to next-to-leading logarithmic (NLL) accuracy.
2. Transverse-Momentum Resummation: Here, the focus is on controlling divergences for small $p_T$ through Fourier transformations into impact parameter space, enabling accurate predictions for cross-section differentials.
3. Joint Resummation: This combines both threshold and $p_T$ resummations to manage contributions across different scales simultaneously, improving predictions where fixed-order expansions fall short.

Implementation and Results

The authors detail the implementation of their computational code in C++ and Fortran, which integrates with standard libraries such as LHAPDF for parton distribution functions. Also critical is the use of the Supersymmetry Les Houches Accord (SLHA) for input data management. The paper convincingly demonstrates the utility of their package through examples using a particular constrained scenario from the Minimal Supersymmetric Standard Model (MSSM), characterized by specific electroweak superpartner masses.

Results display significant stabilization of theoretical predictions across various conditions. For example, supersymmetric particle production cross-sections are computed at the LHC's energy levels, exhibiting enhanced accuracy and reduced scale uncertainties when employing the resummation techniques proposed. These advancements underscore the critical role of resummation in yielding reliable results under experimental conditions characterized by high energies and complex interactions.

Theoretical and Practical Implications

The theoretical framework and computational techniques detailed in this paper have substantial implications for supersymmetric searches at high-energy colliders like the LHC. By offering reduced uncertainties in theoretical predictions, the framework assists in refining experimental data analysis and informs potential discoveries in particle physics beyond the Standard Model. Practically, the computational package presents a robust tool for physicists involved in modeling and simulation of supersymmetric processes, equipping them with advanced methodologies to cross-verify empirical findings against theoretical models.

Future Directions

With potential extensions to incorporate more sophisticated models or apply to broader conditions, this paper lays groundwork for enriched precision in particle physics modeling. Future development could focus on adapting these methods to more complex supersymmetric scenarios or expanding applicability for other high-energy physics phenomena. Moreover, improving computational efficiency and further reducing dependencies could enhance the utilization and adoption of the developed package in diverse research settings.

In conclusion, this paper constitutes a valuable contribution to high precision computational methods in supersymmetric physics, advancing the frontier of theoretical and practical tools available to researchers in the field.