We define benchmark models for SUSY searches at the LHC, including the CMSSM, NUHM, mGMSB, mAMSB, MM-AMSB and p19MSSM, as well as models with R-parity violation and the NMSSM. Within the parameter ...spaces of these models, we propose benchmark subspaces, including planes, lines and points along them. The planes may be useful for presenting results of the experimental searches in different SUSY scenarios, while the specific benchmark points may serve for more detailed detector performance tests and comparisons. We also describe algorithms for defining suitable benchmark points along the proposed lines in the parameter spaces, and we define a few benchmark points motivated by recent fits to existing experimental data.
General NMSSM signatures at the LHC Dreiner, H. K.; Staub, F.; Vicente, A.
Physical review. D, Particles, fields, gravitation, and cosmology,
02/2013, Volume:
87, Issue:
3
Journal Article, Web Resource
Peer reviewed
Open access
We study the possible LHC collider signatures in the next-to-minimal supersymmetric standard model. The general next-to-minimal supersymmetric standard model consists of 29 supersymmetric particles ...which can be mass ordered in 29! Asymptotically = to 9 x 10 super(30) ways. To reduce the number of hierarchies to a more manageable amount we assume a degeneracy of the sfermions of the first two generations with the same quantum numbers. Further assumptions about the neutralino and chargino masses leave 15 unrelated parameters. We check all 15! approximate 10 super(12) relevant mass orderings for the dominant decay chains and the corresponding collider signatures at the LHC. As preferred signatures, we consider charged leptons, missing transverse momentum, jets, and W, Z or Higgs bosons. We present the results for three different choices of the singlet to Higgs coupling lambda: (a) small, O(lambda) < O(Y sub(tau)), (b) large, O(lambda) Asymptotically = to O(Y sub(top), Y sub(b), Y sub(tau)), and (c) dominant, O(lambda) > O(Y sub(top)). We compare these three scenarios with the MSSM expectations as well as among each other. We also mention a possible mass hierarchy leading to seven jets plus one lepton signatures at the LHC and comment briefly on the consequence of possible R-parity violation.
A
bstract
In order to accommodate the observed Higgs boson mass in the CMSSM, the stops must either be very heavy or the mixing in the stop sector must be very large. Lower stop masses, possibly more ...accessible at the LHC, still give the correct Higgs mass only if the trilinear stop mixing parameter |
A
t
| is in the multi-TeV range. Recently it has been shown that such large stop mixing leads to an unstable electroweak vacuum which spontaneously breaks charge or color. In this work we therefore go beyond the CMSSM and investigate the effects of including baryon number violating operators
λ
′
′
U
¯
D
¯
D
¯
on the stop and Higgs sectors. We find that for
λ
′
′
≃
O
0.3
light stop masses as low as 220 GeV are consistent with the observed Higgs mass as well as flavour constraints while allowing for a stable vacuum. The light stop in this scenario is often the lightest supersymmetric particle. We furthermore discuss the importance of the one-loop corrections involving
R
-parity violating couplings for a valid prediction of the light stop masses.
Review of Particle Physics Tanabashi, M.; Nakamura, K.; Tanaka, J. ...
Physical review. D,
08/2018, Volume:
98, Issue:
3
Journal Article
Peer reviewed
Open access
The Review summarizes much of particle physics and cosmology. Using data from previous editions, plus 2,873 new measurements from 758 papers, we list, evaluate, and average measured properties of ...gauge bosons and the recently discovered Higgs boson, leptons, quarks, mesons, and baryons. We summarize searches for hypothetical particles such as supersymmetric particles, heavy bosons, axions, dark photons, etc. Particle properties and search limits are listed in Summary Tables. We give numerous tables, figures, formulae, and reviews of topics such as Higgs Boson Physics, Supersymmetry, Grand Unified Theories, Neutrino Mixing, Dark Energy, Dark Matter, Cosmology, Particle Detectors, Colliders, Probability and Statistics. Among the 118 reviews are many that are new or heavily revised, including a new review on Neutrinos in Cosmology.
A
bstract
Using the example of selected decays driven by R-parity-violating supersymmetric operators, we demonstrate how strong final-state interactions can be controlled quantitatively with high ...precision, thus allowing for a more accurate extraction of effective parameters from data. In our examples we focus on the lepton-flavor-violating decays
τ → μπ
+
π
−
.
InR-parityviolationthesecanariseduetotheproductoftwocouplings. We find bounds that are an order of magnitude stronger than previous ones.
The proposed International Linear Collider (ILC) is well-suited for discovering physics beyond the Standard Model and for precisely unraveling the structure of the underlying physics. The physics ...return can be maximized by the use of polarized beams. This report shows the paramount role of polarized beams and summarizes the benefits obtained from polarizing the positron beam, as well as the electron beam. The physics case for this option is illustrated explicitly by analyzing reference reactions in different physics scenarios. The results show that positron polarization, combined with the clean experimental environment provided by the linear collider, allows to improve strongly the potential of searches for new particles and the identification of their dynamics, which opens the road to resolve shortcomings of the Standard Model. The report also presents an overview of possible designs for polarizing both beams at the ILC, as well as for measuring their polarization.
We analyze the impact of electron and positron beam polarization on radiative neutralino production at the international linear collider (ILC). We focus on three different mSUGRA scenarios in turn at ...the Higgs strahlung threshold, the top pair production threshold, and at
500 GeV. In these scenarios at the corresponding
, radiative neutralino production is the only supersymmetric production mechanism that is kinematically allowed. The heavier neutralinos and charginos as well as the sleptons, squarks and gluinos are too heavy to be pair produced. We calculate the signal cross section and also the standard model background from radiative neutrino production. For our scenarios, we obtain significances larger than 10 and signal to background ratios between 2% and 5%, if we have electron beam polarization
–0.8 and positron beam polarization
–0.3. If we have electron beam polarization of
, then the signal is observable with
but both the significance and the signal to background ratio are significantly improved for
.
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