Adjusting the position of \dot

Question

I'm writing a paper that uses the symbol \dot{\mathcal{U}} which for me (in PDFLaTeX with Palatino math fonts) looks like this:

As you can imagine, from further away, the dot is invisible. Is there some easy way of increasing the space between the character and the dot, or moving it to the right, so it's more visible?

Answer 1

You can define a new macro that provides a slightly displaced dot, say \dispdot[<disp>]{<stuff>}. Below I've defined \dispdot to give a .2ex displacement. Supplying a different <disp> will change the location of the \dot:

\documentclass{article}
\newcommand{\dispdot}[2][.2ex]{\dot{\raisebox{0pt}[\dimexpr\height+#1][\depth]{$#2$}}}% \dispdot[<displace>]{<stuff>}
\begin{document}
$d\mathcal{U}, d\dot{\mathcal{U}}, d\dispdot{\mathcal{U}}, d\dispdot[.5ex]{\mathcal{U}}$
\end{document}

If need be, it would be possible to capture the math style.

---

For horizontal displacement, you could define \dispdot to give a 3mu displacement (actually, due to symmetry it is half the actual displacement):

\documentclass{article}
\newcommand{\dispdot}[2][3mu]{\dot{#2\mkern#1}\mkern-#1}% \dispdot[<disp>]{<stuff>}
\begin{document}
$d\mathcal{U}, d\dot{\mathcal{U}}, d\dispdot{\mathcal{U}}, d\dispdot[5mu]{\mathcal{U}}$
\end{document}

Note that math units are very small, so adjustments will be very tiny.

Answer 2

This answer originally followed the logic of Vertical spacing between character and \hat, but has been revised to handle differernt math sizes, shown below in \textstyle, \scriptstyle, and \scriptscriptstyle.

Setting \dydot adjusts the vertical shift of the dot.

\documentclass{article}
\usepackage{stackengine}
\usepackage{scalerel}% IF YOU NEED IT FOR SCRIPTSTYLE MATH
\def\stacktype{L}
\stackMath
\def\dydot{.2ex}
\newcommand\caldot[1]{\ThisStyle{%
              \stackon[\dydot]{\SavedStyle\mathcal{#1}}
                              {\SavedStyle\dot{\phantom{\mathcal{#1}}}}}}
\begin{document}
\( A \caldot U \)
\(\scriptstyle A \caldot U \)
\(\scriptscriptstyle A \caldot U \)
\end{document}