113,906 research outputs found
Pure Gravity Mediation of Supersymmetry Breaking at the LHC
Supersymmetric theories which can allow for a 125 GeV Higgs mass and also
solve the naturalness and susy flavor problems now require a fair degree of
complexity. Here we consider the simplest possibility for supersymmetry near
the weak scale, but with the requirement of naturalness dropped. In "pure
gravity mediation", all supersymmetric particles except for the gauginos lie at
tens to thousands of TeV, with the gauginos obtaining loop suppressed masses
automatically by anomaly mediation and higgsino threshold corrections. The
gauginos are the lightest superpartners, and we investigate the current
collider constraints on their masses, as well as the future reach of the LHC.
We consider gluino pair production with a jets + missing energy signature, as
well as events with disappearing charged tracks caused by charged winos
decaying into their neutral partners. We show that presently, gluino masses
less than about 1 TeV and wino masses less than about 300 GeV are excluded, and
that the 14 TeV LHC can probe gluino masses up to about 2 TeV and wino masses
up to 1 TeV.Comment: 22 pages, 5 figure
On the Numerical Evaluation of One-Loop Amplitudes: the Gluonic Case
We develop an algorithm of polynomial complexity for evaluating one-loop
amplitudes with an arbitrary number of external particles. The algorithm is
implemented in the Rocket program. Starting from particle vertices given by
Feynman rules, tree amplitudes are constructed using recursive relations. The
tree amplitudes are then used to build one-loop amplitudes using an integer
dimension on-shell cut method. As a first application we considered only three
and four gluon vertices calculating the pure gluonic one-loop amplitudes for
arbitrary external helicity or polarization states. We compare our numerical
results to analytical results in the literature, analyze the time behavior of
the algorithm and the accuracy of the results, and give explicit results for
fixed phase space points for up to twenty external gluons.Comment: 22 pages, 9 figures; v2: references added, version accepted for
publicatio
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