\begin{tikzpicture}

% draw D-branes
\draw[thick] (0cm, -1cm) -- (1.7cm, 4cm) node[anchor=west] {$D_{(t)}$};
\draw[thick] (-0.5cm, -0.5cm) -- (4cm, 2cm) node[anchor=west] {$D_{(t+1)}$};

% draw baseline and angles
\draw[dotted] (-1cm, -0.05cm) -- (5cm, -0.05cm);
\draw[->] (2.5cm, -0.05cm) node[anchor=north] {$\alpha_{(t)}$} arc (0:62:2.6cm);
\draw[->] (1.5cm, -0.05cm) node[anchor=north] {$\alpha_{(t+1)}$} arc (0:22:1.6cm);
\draw[->] (0.55cm, 0.6cm) node[anchor=south east] {$\varepsilon_{(t)}$} arc (76:210:0.6cm);

\end{tikzpicture}

% vim: ft=tex