Phenomenology of anomaly-mediated supersymmetry-breaking scenarios with nonminimal flavor violation

In minimal anomaly-mediated supersymmetry-breaking models, tachyonic sleptons are avoided by introducing a common scalar mass similar to the one introduced in minimal supergravity. This may lead to nonminimal flavor-violating interactions, e.g., in the squark sector. In this paper, we analyze the viable anomaly-mediated supersymmetry-breaking parameter space in the light of the latest limits on low-energy observables and LHC searches, complete our analytical calculations of flavor-violating supersymmetric particle production at hadron colliders with those related to gluino production, and study the phenomenological consequences of nonminimal flavor violation in anomaly-mediated supersymmetry-breaking scenarios at the LHC. Related cosmological aspects are also briefly discussed.

Figure 1

Scans of the minimal AMSB parameter space, where all flavor-violating parameters, apart from the CKM matrix, vanish, in the $(m_0,m_{3/2})$ plane at fixed $\tan \beta =10$ (left panel), in the $(\tan \beta ,m_{3/2})$ plane at fixed $m_0=1\mathrm{TeV}$ (central panel) and in the $(\tan \beta ,m_0)$ plane at fixed $m_{3/2}=60\mathrm{TeV}$ (right panel). We show regions where there is no physical solution to the renormalization-group equations (grey), or which are excluded by the constraints related to the $b\to s\gamma$ branching ratio (blue) and the Higgs mass (red). The regions, where the agreement between theory and experiment for the anomalous magnetic moment of the muon is restored, are presented in beige. On the left panel, we also indicate the region where the mass of the lightest Higgs boson is close to 125 GeV (green) and the exclusion limit obtained (crosses) from the reinterpretation of the LHC results on supersymmetric particle searches in the context of AMSB scenarios (see Ref. 53).

Figure 2

Typical scans of NMFV AMSB scenarios in the $(m_0,m_{3/2})$ plane with a fixed value of $\tan \beta =10$. The sign of the $\mu$ parameter is chosen positive and we present the results for different values of the NMFV parameters ${\lambda }_{\mathrm{L}}$ (upper panels), ${\lambda }_u$ (central panels) and ${\lambda }_d$ (lower panels). We show regions excluded due to the absence of physical solutions to the renormalization-group equations (grey), by the constraints associated to the $b\to s\gamma$ branching ratio (blue) and the Higgs mass (red).

Figure 3

Scans of NMFV AMSB scenarios in the $(\tan \beta ,m_{3/2})$ plane with a fixed value of $m_0=1\mathrm{TeV}$ (upper panels) and in the $(\tan \beta ,m_0)$ plane with a fixed value of $m_{3/2}=60\mathrm{TeV}$ (lower panels). The sign of the $\mu$ parameter is chosen positive and we present the results for different values of the NMFV parameter ${\lambda }_L$. We show regions excluded due to the absence of physical solutions to the renormalization-group equations (grey), by the constraints associated to the $b\to s\gamma$ branching ratio (blue), the $B_s^0$-meson branching to a muon pair $\mathrm{BR}(B_s^0\to {\mu }^{+}{\mu }^{-})$ (green) and the lightest Higgs-boson mass (red).

Figure 4

$({\lambda }_{\mathrm{L}},{\lambda }_u)$ (upper panel) and $({\lambda }_{\mathrm{L}},{\lambda }_d)$ (lower panel) planes for the three scenarios I (left), II (center) and III (right) presented in Table . We show regions excluded due to the absence of physical solutions for the diagonalization of the mass matrices at the one-loop level (grey), the constraints associated to the $b\to s\gamma$ branching ratio (blue) and the $B$-meson mass difference $\Delta M_{B_s^0}$ (purple).

Figure 5

Dependence of masses and flavor decomposition of the lightest, second lightest, and heaviest down-type squarks on the flavor-violating parameter ${\lambda }_d$ for the scenario I of Table .

Figure 6

Same as Fig. 5 for the scenario II of Table .

Figure 7

Same as Fig. 5 for the scenario III of Table .

Figure 8

Dependence of $\mathrm{BR}(b\to s\gamma )$, $\mathrm{BR}(b\to s\mu \mu )$, and $\Delta M_{B_s^0}$ on the flavor-violating parameter ${\lambda }_L$ for the scenario I of Table . We also show horizontal lines corresponding to the experimental upper and lower limits for $\mathrm{BR}(b\to s\gamma )$ (blue dashed line), $\mathrm{BR}(b\to s\mu \mu )$ (red dotted line), and $\Delta M_{B_s^0}$ (blue dashed line), as discussed in Sec. 3a.

Figure 9

Same as Fig. 8 for the scenario II of Table .

Figure 10

Same as Fig. 8 for the scenario III of Table .

Figure 11

Tree-level Feynman diagrams for the production of a pair of gluinos in quark-antiquark (top) and gluon-gluon collisions (bottom).

Figure 12

Tree-level Feynman diagrams for the associated production of gluinos and squarks.

Figure 13

Tree-level Feynman diagrams for the associated production of gluinos and gauginos.

Figure 14

Cross sections of gluino production in association with up- and down-type squarks for various ranges of the flavor-mixing parameters ${\lambda }_L$, ${\lambda }_u$, and ${\lambda }_d$ for the reference scenario I of Table .

Figure 15

Same as Fig. 14 for reference scenario II.

Figure 16

Same as Fig. 14 for reference scenario III.

Figure 17

Left: Isolines corresponding to ${\Omega }_{{\tilde{\chi }}_1^0}{h}^2=0.1123$ in the $m_{\Phi }–m_{{\tilde{\chi }}_1^0}$ planes for different values of $⟨\sigma v⟩$. The dotted lines correspond to $m_{{\tilde{\chi }}_1^0}=175\mathrm{GeV}$ and $m_{\Phi }=m_{3/2}=60\mathrm{TeV}$. Right: The neutralino relic density ${\Omega }_{{\tilde{\chi }}_1^0}{h}^2$ from gravitino decay as a function of the reheating temperature $T_R$ for a typical AMSB scenarios with $m_{{\tilde{\chi }}_1^0}=175\mathrm{GeV}$, $m_{3/2}=60\mathrm{TeV}$, as it is the case for the scenarios of Table . The solid line includes a contribution of ${\Omega }_{\tilde{\chi }}{h}^2=8–{10}^{-4}$ from thermal neutralinos, while the dashed line indicates the contribution from gravitino decay only.