Probing nonthermal gravitinos through large-scale structure observations

We investigate the effects of nonthermally produced dark matter on large-scale structure formation, focusing on the gravitino dark matter. Our analysis shows that large-scale structure measurements from the Sloan Digital Sky Survey (SDSS) luminous red galaxy (LRG) data offer a promising approach to probing nonthermally produced gravitinos. Specifically, if gravitinos resulting from neutralino decay constitute a fraction <a:math xmlns:a="http://www.w3.org/1998/Math/MathML" display="inline"><a:msub><a:mi>F</a:mi><a:mi>dec</a:mi></a:msub><a:mo>=</a:mo><a:mn>0.35</a:mn><a:mo stretchy="false">(</a:mo><a:mn>0.1</a:mn><a:mo stretchy="false">)</a:mo></a:math> of the dark matter component, the data exclude binolike neutralino with a mass <e:math xmlns:e="http://www.w3.org/1998/Math/MathML" display="inline"><e:msub><e:mi>m</e:mi><e:msubsup><e:mi>χ</e:mi><e:mn>1</e:mn><e:mn>0</e:mn></e:msubsup></e:msub><e:mo>≲</e:mo><e:mn>25</e:mn><e:mo stretchy="false">(</e:mo><e:mn>11</e:mn><e:mo stretchy="false">)</e:mo><e:mtext> </e:mtext><e:mtext> </e:mtext><e:mi>GeV</e:mi></e:math> at 95% C.L. Furthermore, this constraint appears to be largely independent of the gravitino mass.