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This project is supported by U.S. DOE, U.S. NSF, CONACYT, and PAPIIT-DGAPA

Partial Waves

We present the codes and the online webpage for the calculation of the partial waves $R^{I,kj}_{\ell \tau}(s)$.

Notation

All the channels are treated as two-body (meson-baryon) states and are labeled as follows:
(i) if the state has the same orbital angular momentum ($\ell$) as the partial wave the channel is identified by the names of the meson and the baryon, e.g. $\bar{K}N$ or $\pi \Sigma$;
(ii) if the baryon has spin $3/2$, as it is the case of $\Sigma (1385)$, $\Delta (1232)$ and $\Lambda (1520)$ (in what follows $\Sigma^*$, $\Delta$ and $\Lambda^*$ respectively), the orbital angular momentum of the initial state does not correspond to $\ell$ and a subindex $L$ is added denoting the angular momentum of the initial (final) state. For example, in ${\bar K} N$ system the $S_{01}$ denotes the isoscalar, $l=0$ partial wave with total spin $J=1$. It may couple to $\pi \Sigma^*$ with orbital angular momentum $L=2$ ($D$ wave) which we label as $\left[ \pi \Sigma^*\right]_D$;
(iii) if the state contains a spin one $\bar{K}^*$ and a nucleon, they can couple to spin $1/2$ which we name $\bar{K}_1^*N$ or to spin $3/2$ which we name $\bar{K}_3^*N$. The $\bar{K}_1^*N$ state has the same orbital angular momentum as the $\bar K N$ and the partial wave but the $\bar{K}_3^*N$ does not, hence we add a $L$ subindex to the last. For example, the $S_{01}$ partial wave has as possible states $\bar{K}_1^*N$ and $\left[ \bar{K}_3^*N\right]_D$.

For every partial wave we include an additional meson-hyperon channel that collectively accounts for any any missing inelasticity arising from channels not included explicitly. The kinematical variables for such a dummy channel is chosen arbitrarily as if it was a two-pion $\Lambda$ or $\Sigma$ state labeled as $\pi \pi \Lambda$ for $I=0$ and $\pi \pi \Sigma$ for $I=1$ partial waves. All the channels incorporated in the model have single-energy partial-wave data to fit except for the dummy channels $\pi\pi\Lambda$ and $\pi\pi\Sigma$ and the $\eta \Lambda$ and $\eta \Sigma$ channels in the $S$ waves.

The full list of initial (final) states for each partial wave is:

  • $S_{01}$:$\bar{K}N$, $\pi \Sigma$, $\eta \Lambda$, $\bar{K}^*_{1}N$, $\left[ \bar{K}^*_{3}N\right]_D$, $\left[ \pi \Sigma^*\right]_D$, $\pi \pi \Lambda$;
  • $P_{01}$: $\bar{K}N$, $\pi \Sigma$, $\bar{K}^*_{1}N$, $\left[ \bar{K}^*_{3}N\right]_P$, $\left[ \pi \Sigma^*\right]_P$, $\pi \pi \Lambda$;
  • $P_{03}$: $\bar{K}N$, $\pi \Sigma$, $\bar{K}^*_{1}N$, $\left[ \bar{K}^*_{3}N\right]_P$, $\left[ \bar{K}^*_{3}N\right]_F$, $\left[ \pi \Sigma^*\right]_P$, $\left[ \pi \Sigma^*\right]_F$, $\pi \pi \Lambda$;
  • $D_{03}$: $\bar{K}N$, $\pi \Sigma$, $\bar{K}^*_{1}N$, $\left[ \pi \Sigma^*\right]_S$, $\left[ \pi \Sigma^*\right]_D$, $\pi \pi \Lambda$;
  • $D_{05}$: $\bar{K}N$, $\pi \Sigma$, $\left[ \pi \Sigma^*\right]_D$, $\left[ \pi \Sigma^*\right]_G$, $\pi \pi \Lambda$;
  • $F_{05}$: $\bar{K}N$, $\pi \Sigma$, $\bar{K}^*_{1}N$, $\left[ \bar{K}^*_{3}N\right]_P$, $\left[ \bar{K}^*_{3}N\right]_F$, $\left[ \pi \Sigma^*\right]_P$, $\left[ \pi \Sigma^*\right]_F$, $\pi \pi \Lambda$;
  • $F_{07}$: $\bar{K}N$, $\pi \Sigma$, $\bar{K}^*_{1}N$, $\pi \pi \Lambda$;
  • $G_{07}$: $\bar{K}N$, $\pi \Sigma$, $\bar{K}^*_{1}N$, $\left[ \bar{K}^*_{3}N\right]_D$, $\left[ \bar{K}^*_{3}N\right]_G$, $\pi \pi \Lambda$;
  • $S_{11}$: $\bar{K}N$, $\pi \Sigma$, $\pi \Lambda$, $\eta \Sigma$, $\bar{K}^*_{1}N$, $\left[ \bar{K}^*_{3}N\right]_D$, $\left[ \pi \Sigma^*\right]_D$, $\left[ \pi \Lambda^*\right]_P$, $\left[ \bar{K} \Delta \right]_D$, $\pi \pi \Sigma$;
  • $P_{11}$: $\bar{K}N$, $\pi \Sigma$, $\pi \Lambda$, $\bar{K}^*_{1}N$, $\left[ \bar{K}^*_{3}N\right]_P$, $\left[ \pi \Sigma^*\right]_P$, $\left[ \pi \Lambda^*\right]_D$, $\left[ \bar{K} \Delta \right]_P$, $\pi \pi \Sigma$;
  • $P_{13}$: $\bar{K}N$, $\pi \Sigma$, $\pi \Lambda$, $\bar{K}^*_{1}N$, $\left[ \bar{K}^*_{3}N\right]_P$, $\left[ \pi \Sigma^*\right]_P$, $\left[ \pi \Lambda^*\right]_D$, $\left[ \pi \Sigma^*\right]_F$, $\left[ \pi \Lambda^*\right]_S$, $\left[ \bar{K} \Delta \right]_P$, $\pi \pi \Sigma$;
  • $D_{13}$: $\bar{K}N$, $\pi \Sigma$, $\pi \Lambda$, $\bar{K}^*_{1}N$, $\left[ \bar{K}^*_{3}N\right]_S$, $\left[ \bar{K}^*_{3}N\right]_D$, $\left[ \pi \Sigma^*\right]_S$, $\left[ \pi \Sigma^*\right]_D$, $\left[ \pi \Lambda^*\right]_P$, $\left[ \pi \Lambda^*\right]_F$, $\left[ \bar{K} \Delta \right]_S$, $\left[ \bar{K} \Delta \right]_D$, $\pi \pi \Sigma$;
  • $D_{15}$: $\bar{K}N$, $\pi \Sigma$, $\pi \Lambda$, $\bar{K}^*_{1}N$, $\left[ \bar{K}^*_{3}N\right]_D$, $\left[ \pi \Sigma^*\right]_D$, $\left[ \pi \Sigma^*\right]_G$, $\left[ \pi \Lambda^*\right]_P$, $\left[ \pi \Lambda^*\right]_F$, $\left[ \bar{K} \Delta \right]_D$, $\pi \pi \Sigma$;
  • $F_{15}$: $\bar{K}N$, $\pi \Sigma$, $\pi \Lambda$, $\bar{K}^*_{1}N$, $\left[ \bar{K}^*_{3}N\right]_P$, $\left[ \bar{K}^*_{3}N\right]_F$, $\left[ \pi \Sigma^*\right]_P$, $\left[ \pi \Sigma^*\right]_F$, $\left[ \pi \Lambda^*\right]_D$, $\left[ \pi \Lambda^*\right]_G$, $\left[ \bar{K} \Delta \right]_P$, $\pi \pi \Sigma$;
  • $F_{17}$: $\bar{K}N$, $\pi \Sigma$, $\pi \Lambda$, $\bar{K}^*_{1}N$, $\left[ \bar{K}^*_{3}N\right]_F$, $\left[ \bar{K}^*_{3}N\right]_H$, $\left[ \pi \Sigma^*\right]_F$, $\left[ \pi \Lambda^*\right]_D$, $\left[ \pi \Lambda^*\right]_G$, $\left[ \bar{K} \Delta \right]_F$, $\pi \pi \Sigma$;
  • $G_{17}$: $\bar{K}N$, $\pi \Sigma$, $\pi \Lambda$, $\bar{K}^*_{1}N$, $\left[ \bar{K}^*_{3}N\right]_G$, $\left[ \pi \Lambda^*\right]_F$, $\left[ \pi \Lambda^*\right]_H$, $\left[ \bar{K} \Delta \right]_D$, $\left[ \bar{K} \Delta \right]_G$, $\pi \pi \Sigma$.

Fortran Code

  • Partial Waves Fortran code and input: zip file
  • Contact person: Cesar Fernandez-Ramirez
  • Last update: September 2015
  • Zip File Content:
    • README file: README.tex and README.pdf
    • Fortran Source File: partialwaves.f
    • Parameter files (contain the parameters for each partial wave):
      • parameters.s01.inp
      • parameters.p01.inp
      • parameters.p03.inp
      • parameters.d03.inp
      • parameters.d05.inp
      • parameters.f05.inp
      • parameters.f07.inp
      • parameters.g07.inp
      • parameters.s11.inp
      • parameters.p11.inp
      • parameters.p13.inp
      • parameters.d13.inp
      • parameters.d15.inp
      • parameters.f15.inp
      • parameters.f17.inp
      • parameters.g17.inp
    • Input File: file.inp
    • Example of input file (file.inp):

      
                  s01
      
                  1 1
      
                  2.5
      
                  4.5
      
                  100
      
                  

      • The first line indicates the partial wave, the options are:

        • all $\to$ computes all the partial waves for a given channel
        • s01 $\to S_{01}$
        • p01 $\to P_{01}$
        • p03 $\to P_{03}$
        • d03 $\to D_{03}$
        • d05 $\to D_{05}$
        • f05 $\to F_{05}$
        • f07 $\to F_{07}$
        • g07 $\to G_{07}$
        • s11 $\to S_{11}$
        • p11 $\to P_{11}$
        • p13 $\to P_{13}$
        • d13 $\to D_{13}$
        • d15 $\to D_{15}$
        • f15 $\to F_{15}$
        • f17 $\to F_{17}$
        • g17 $\to G_{17}$

      • The second line indicates the process.
        It is made of two numbers where the first refers to the initial state and the last to the final.
        The options are:

        • 1 $\to \bar{K}N$,
        • 2 $\to \pi \Sigma$,
        • 3 $\to \pi \Lambda$,
        • 4 $\to \eta \Lambda$,
        • 5 $\to \eta \Sigma$,
        • 6 $\to \bar{K}_1 N$,
        • 7 $\to \left[ \bar{K}_3 N \right]_-$,
        • 8 $\to \left[ \bar{K}_3 N \right]_+$,
        • 9 $\to \left[ \pi \Sigma^* \right]_-$,
        • 10 $\to \left[ \pi \Sigma^* \right]_+$,
        • 11 $\to \left[ \bar{K} \Delta \right]_-$,
        • 12 $\to \left[ \bar{K} \Delta \right]_+$,
        • 13 $\to \left[ \pi \Lambda(1520) \right]_-$,
        • 14 $\to \left[ \pi \Lambda(1520) \right]_+$,
        • 15 $\to \pi \pi \Lambda$,
        • 16 $\to \pi \pi \Sigma$.

        The $+$ and $-$ subindices are short for the angular momentum of the state.
        The $+$ stands for the higher angular momentum and $-$ for the lower.
        If only one state of angular momentum is possible it corresponds to the $+$ state.

        Examples:
        • Example 1: For any partial wave, 1 2 computes $\bar{K}N \to \pi \Sigma$.
        • Example 2: For partial wave $S_{01}$, 15 10 computes $\pi \pi \Lambda \to \left[ \pi \Sigma(1385)\right]_D$.
        • Example 3: For partial wave $F_{05}$, 8 7 computes $\left[ \bar{K}^*_3 N \right]_F \to \left[ \bar{K}^*_3 N \right]_P$.

      • The third line indicates the starting value of $s$ in GeV$^2$.

      • The fourth line indicates the final value of $s$ in GeV$^2$.

      • The fifth line indicates the the amount of points to calculate.
        There is a limit of 1000 points.
        It can be changed modifying variable max_data_points=1000 in module resonancesizes.

Online version

The online version of the code is the same as the one available for download except for some built-in functionalities aimed to allow the webpage to produce nicer plots.
The webpage has integrated some restrictions in the inputs through drop-down menus, kinematical ranges and number of points to calculate.
The available range for $s$ is $\left[1.5 , 5.0 \right]$ GeV$^2$ where $s$ is energy squared in the center of mass frame.
There is a limit of 1000 points to calculate.
Any initial and final state can be selected. If that state is not present in the partial wave it will yield a zero result.

Output

The online and the downloadable versions produce an output file (output.txt) which contains six columns:

    (i)     $s$ (GeV$^2$),
    (ii)   $~E_{lab}$ (GeV),
    (iii)  $~p_{lab}$ (GeV),
    (iv)   the center of mass incoming momentum squared $q^2$ (GeV$^2$),
    (v)    real part of the partial wave (adimensional), and
    (vi)   imaginary part of the partial wave (adimensional).
If the process is not kinematically allowed $p_{lab}=0$ in the output file.
The online version also produces a figure of the partial wave vs $s$.
If the selected partial is "all", the partial waves are written in files pw.s01.txt, pw.p01.txt, and so on.
The webpage generates a downloable output.zip file with all the partial waves in it.

Run online version of the code

Select Partial Wave:

Select Initial State: Select Final State: