Possible unconventional pairing in <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:msub><mml:mrow><mml:mo>(</mml:mo><mml:mi>Ca</mml:mi><mml:mo>,</mml:mo><mml:mi>Sr</mml:mi><mml:mo>)</mml:mo></mml:mrow><mml:mn>3</mml:mn></mml:msub><mml:msub><mml:mrow><mml:mo>(</mml:mo><mml:mi>Ir</mml:mi><mml:mo>,</mml:mo><mml:mi>Rh</mml:mi><mml:mo>)</mml:mo></mml:mrow><mml:mn>4</mml:mn></mml:msub><mml:msub><mml:mi>Sn</mml:mi><mml:mn>13</mml:mn></mml:msub></mml:mrow></mml:math> …

We study the evolution of temperature-dependent resistivity with controlled point-like disorder induced by 2.5 MeV electron irradiation in stoichiometric compositions "3-4-13" stannides, $(\text{Ca,Sr})_{3}(\text{Ir,Rh})_{4}\text{Sn}_{13}$.Three these cubic compounds exhibit a microscopic coexistence charge-density wave (CDW) order and superconductivity (SC), while $\text{Ca}_{3}\text{Rh}_{4}\text{Sn}_{13}$ does not develop CDW order. As expected, transition temperature, $T_{\text{CDW}}$, is universally suppressed all three compositions. The superconducting $T_{c}$, behaves more complex manner. In $\text{Sr}_{3}\text{Rh}_{4}\text{Sn}_{13}$, it increases initially way consistent direct competition SC, but quickly saturates at higher doses. other compounds, $T_{c}$ monotonically irradiation. strongest suppression found $\text{Ca}_{3}\text{Rh}_{4}\text{Sn}_{13}$, which have further examine this composition measuring London penetration depth, $\lambda(T)$, from we derive superfluid density. result unambiguously points to weak-coupling, full single gap, isotropic state. Therefore, must explain two seemingly incompatible experimental observations: gap significant non-magnetic disorder. conduct quantitative theoretical analysis based on generalized Anderson theorem an unconventional multiband $s^{+-}$-pairing state where sign parameter different one (or small subset) smaller Fermi surface sheets, remains overall fully-gapped.