Tau decay (Christmas theme)

Christmas theme of tau decay in a particle physics detector.

Edit and compile if you like:

% Author: Izaak Neutelings (July 2017)
\documentclass[border=3pt,tikz]{standalone}
%\documentclass{article}
\usepackage{amsmath} % for \text
\usepackage{bm} % for bold math
\usepackage{tikz}
\tikzset{>=latex} % for LaTeX arrow head
\colorlet{myblue}{blue!40!black}
\colorlet{myred}{red!80!black}
\colorlet{mygreen}{green!60!black}
\colorlet{mygold}{yellow!70!orange!90!black}
\usetikzlibrary{arrows.meta}

% vertical custom shading
%https://tex.stackexchange.com/questions/191735/is-it-possible-to-define-the-position-of-top-bottom-and-middle-color-in-fill
\makeatletter
\tikzset{vertical custom shading/.code={%
  \pgfmathsetmacro\tikz@vcs@middle{#1}
  \pgfmathsetmacro\tikz@vcs@bottom{\tikz@vcs@middle/2}
  \pgfmathsetmacro\tikz@vcs@top{(100-\tikz@vcs@middle)/2+\tikz@vcs@middle}
  \pgfdeclareverticalshading[tikz@axis@top,tikz@axis@middle,tikz@axis@bottom]{newaxis}{100bp}{%
    color(0bp)=(tikz@axis@bottom);
    color(\tikz@vcs@bottom bp)=(tikz@axis@bottom);
    color(\tikz@vcs@middle bp)=(tikz@axis@middle);
    color(\tikz@vcs@top bp)=(tikz@axis@top);
    color(100bp)=(tikz@axis@top)}
    \pgfkeysalso{/tikz/shading=newaxis}
  }
}
\makeatother

\begin{document}



% arrow style
\usetikzlibrary{decorations.markings}
\tikzset{->-/.style={decoration={markings,
                               mark=at position .7 with {\arrow[scale=1,mygold]{>}}},
                               postaction={decorate}}}

% photon
\usetikzlibrary{decorations.pathmorphing}
\tikzset{photon/.style={decorate, decoration={snake,segment length=5,amplitude=1.1}}}

% cone style
\usetikzlibrary{shadows.blur}
\tikzset{mycone/.pic={
       \shadedraw[top color=white, bottom color=black!50,shading angle=50,vertical custom shading=10]
                    (-0.4,0.99) -- (0,0) -- (0.4,0.99);
       \shadedraw[top color=white, bottom color=black!20,shading angle=90]
                    (0,1) ellipse (0.4 and 0.12);}}





% TAU DECAY MODE 10 only
\begin{tikzpicture}[scale=0.9,line width=2,mygreen] %,every node/.style={mygold}]
  
  \large
  
  % photon
  \usetikzlibrary{decorations.pathmorphing}
  \tikzset{photon/.style={decorate, decoration={snake,segment length=5,amplitude=1.1}}}
  
  % cone style
  \usetikzlibrary{shadows.blur}
  \tikzset{mycone/.pic={
           \shadedraw[top color=mygreen!40, bottom color=myred!90,shading angle=50,vertical custom shading=10]
                        (-0.4,0.99) -- (0,0) -- (0.4,0.99);
           \shadedraw[top color=mygreen!40, bottom color=mygold!20,shading angle=90]
                        (0,1) ellipse (0.4 and 0.12);}};
  
  \def\R{10}             % inner radius
  \def\hca{14}           % half central angle
  \def\hcl{\R*sin(\hca)} % half chord length c = 2Rsin(theta/2)
  \def\tracker{3}        % tracker
  \def\ECAL{4.8}         % ECAL
  \def\HCAL{7.2}         % HCAL
  \def\hclmax{(\R+\HCAL)*sin(\hca)} % mac
  
  % detectors
  \foreach \r in {\tracker,\ECAL,\HCAL}{
    \draw[thick,myred]
      (0,\r) arc (90:90-\hca:\R+\r)
      (0,\r) arc (90:90+\hca:\R+\r);
  }
  \node[left=0,above left,myred] at ({1.1*\hclmax},{0.10*\tracker}) {tracker};
  \node[left=0,above left,myred] at ({1.1*\hclmax},\tracker) {ECAL};
  \node[left=0,above left,myred] at ({1.1*\hclmax},\ECAL) {HCAL};
  
  % DM 10
  \begin{scope}[shift={(0,0)}, rotate=-3]
    \node[below,mygold] (0,0) {$\bm{\tau^\pm}$};
    \node[right=14pt,below=18,mygold] at (0,0) {$\bm{\tau^\pm\to\text{\bf{a}}_1^\pm\nu_\tau\to\pi^\pm\pi^\mp\pi^\pm\nu_\tau}$};
    \draw[->-] % tau
      (0,0) -- (0,0.7) coordinate (tau);
    \draw[->-,dotted] % neutrinos
      (tau) --+ (40:1.5) node[above right,mygold] {$\bm{\nu_\tau}$};
    \draw[->-] % a1
      (tau) --+ (110:0.5) coordinate (a1) node[midway,left,mygold] {$\bm{\text{\bf{a}}_1^\pm}$};
    \draw[->-] % rho
      (a1)  --+ (124:0.8) coordinate (rho) node[midway,left,mygold] {$\bm{\rho^0}$};
    \draw[->-,rotate= 36] % pion 1
      (rho) --+ (0,3.0) node[left=10,above=38,mygold] {$\bm{\pi^\pm}$}
      pic[rotate=30,scale=1.2] {mycone};
    \draw[->-] % pion 2
      (rho) --+ (85:2.7) node[right=15,above=38,mygold] {$\bm{\pi^\mp}$}
      pic[rotate=-5,scale=1.2] {mycone};
    \draw[->-] % pion 3
      (a1)  --+ (66:3.9) node[right=29,above=33,mygold] {$\bm{\pi^\pm}$}
      pic[rotate=-28,scale=1.2] {mycone};
  \end{scope}
  
\end{tikzpicture}



\end{document}