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      -------- Forwarded Message --------
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            <th align="RIGHT" nowrap="nowrap" valign="BASELINE">Subject:
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            <td>Physics Colloquium Friday, January 20, 2017</td>
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            <th align="RIGHT" nowrap="nowrap" valign="BASELINE">Date: </th>
            <td>Thu, 12 Jan 2017 21:51:06 +0000</td>
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            <th align="RIGHT" nowrap="nowrap" valign="BASELINE">From: </th>
            <td>Wilkinson, Eleonor V <a class="moz-txt-link-rfc2396E" href="mailto:evwilk@wm.edu"><evwilk@wm.edu></a></td>
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            <th align="RIGHT" nowrap="nowrap" valign="BASELINE">To: </th>
            <td><a class="moz-txt-link-abbreviated" href="mailto:physics0607@physics.wm.edu">physics0607@physics.wm.edu</a>
              <a class="moz-txt-link-rfc2396E" href="mailto:physics0607@physics.wm.edu"><physics0607@physics.wm.edu></a></td>
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            <th align="RIGHT" nowrap="nowrap" valign="BASELINE">CC: </th>
            <td><a class="moz-txt-link-abbreviated" href="mailto:undergrads0607@physics.wm.edu">undergrads0607@physics.wm.edu</a>
              <a class="moz-txt-link-rfc2396E" href="mailto:undergrads0607@physics.wm.edu"><undergrads0607@physics.wm.edu></a></td>
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        <p class="MsoPlainText"><b><u><span
                style="font-size:14.0pt;font-family:"Times New
                Roman",serif;color:blue">Colloquium</span></u></b><b><span
              style="font-size:14.0pt;font-family:"Times New
              Roman",serif;color:blue"> 
            </span></b><b><span
              style="font-size:14.0pt;font-family:"Times New
              Roman",serif">                                   
              <span style="color:#1F497D">  </span> <u><span
                  style="color:blue">Randolf Pohl</span></u>  </span></b><span
            style="font-size:14.0pt;font-family:"Times New
            Roman",serif">[Host: T. Averett]<b><o:p></o:p></b></span></p>
        <p class="MsoPlainText"><span
            style="font-size:14.0pt;font-family:"Times New
            Roman",serif">Friday, January 20, 2017                 
              Johannes Gutenberg-University Mainz, Germany and
            Max-Planck-Institute of Quantum Optics, Garching, Germany<o:p></o:p></span></p>
        <p class="MsoPlainText"><span
            style="font-size:14.0pt;font-family:"Times New
            Roman",serif">4:00
            PM                                             
            <b>“<em>Shrinking the proton - Laser spectroscopy for
                nuclear physics and fundamental constants”</em></b><o:p></o:p></span></p>
        <p class="MsoPlainText"><span
            style="font-size:14.0pt;font-family:"Times New
            Roman",serif">Small Hall, Room 111<o:p></o:p></span></p>
        <p class="MsoPlainText"><span
            style="font-size:14.0pt;font-family:"Times New
            Roman",serif"><o:p> </o:p></span></p>
        <p class="MsoPlainText"><b><span
              style="font-size:14.0pt;font-family:"Times New
              Roman",serif;color:blue">Abstract:<o:p></o:p></span></b></p>
        <p class="MsoPlainText"><span
            style="font-size:14.0pt;font-family:"Times New
            Roman",serif">For more than a decade, the rms charge
            radius of the proton was known to be 0.88fm, with about 1%
            uncertainty [1]. Two methods, elastic electron scattering
            and precision laser spectroscopy of atomic hydrogen, yielded
            consistent values.<o:p></o:p></span></p>
        <p class="MsoPlainText"><span
            style="font-size:14.0pt;font-family:"Times New
            Roman",serif"><o:p> </o:p></span></p>
        <p class="MsoPlainText"><span
            style="font-size:14.0pt;font-family:"Times New
            Roman",serif">In 2010, our result from laser
            spectroscopy of the exotic "muonic hydrogen" atom yielded a
            4% smaller value, 0.84 fm, with an uncertainty of less than
            0.1% [2,3]. In muonic hydrogen, a negative muon orbits a
            proton with a 200 times<o:p></o:p></span></p>
        <p class="MsoPlainText"><span
            style="font-size:14.0pt;font-family:"Times New
            Roman",serif">smaller Bohr orbit than in regular
            hydrogen, which increases the sensitivity of muonic hydrogen
            to the proton charge radius by 200^3 ~ 10 million! Since
            2010, the discrepancy increased to more than 7 sigmas [4],
            making it one<o:p></o:p></span></p>
        <p class="MsoPlainText"><span
            style="font-size:14.0pt;font-family:"Times New
            Roman",serif">of the biggest discrepancies in the
            Standard Model.<o:p></o:p></span></p>
        <p class="MsoPlainText"><span
            style="font-size:14.0pt;font-family:"Times New
            Roman",serif"><o:p> </o:p></span></p>
        <p class="MsoPlainText"><span
            style="font-size:14.0pt;font-family:"Times New
            Roman",serif">I will discuss the so-called "proton
            radius puzzle" [5], report on more measurements in muonic
            atoms [6], and the result of a new measurement in regular
            atomic hydrogen.<o:p></o:p></span></p>
        <p class="MsoPlainText"><span
            style="font-size:14.0pt;font-family:"Times New
            Roman",serif"><o:p> </o:p></span></p>
        <p class="MsoPlainText"><span
            style="font-size:14.0pt;font-family:"Times New
            Roman",serif">[1] P.J. Mohr et al. (CODATA 2006), Rev.
            Mod. Phys. 80, 633 (2008)<o:p></o:p></span></p>
        <p class="MsoPlainText"><span
            style="font-size:14.0pt;font-family:"Times New
            Roman",serif">[2] Pohl et al. (CREMA coll.), Nature
            466, 213 (2010)<o:p></o:p></span></p>
        <p class="MsoPlainText"><span
            style="font-size:14.0pt;font-family:"Times New
            Roman",serif">[3] Antognini et al.,(CREMA coll.),
            Science 339, 417 (2013)<o:p></o:p></span></p>
        <p class="MsoPlainText"><span
            style="font-size:14.0pt;font-family:"Times New
            Roman",serif">[4] Olive et al. (PDG 2014), Chin. Phys.
            C40, 090001 (2014)<o:p></o:p></span></p>
        <p class="MsoPlainText"><span
            style="font-size:14.0pt;font-family:"Times New
            Roman",serif">[5] Pohl et al., Annu. Rev. Nucl. Part.
            Sci 63, 175 (2013)<o:p></o:p></span></p>
        <p class="MsoPlainText"><span
            style="font-size:14.0pt;font-family:"Times New
            Roman",serif">[6] Pohl et al. (CREMA coll.), Science
            353, 669 (2016)<o:p></o:p></span></p>
        <p class="MsoPlainText"><span
            style="font-size:14.0pt;font-family:"Times New
            Roman",serif"><o:p> </o:p></span></p>
        <p class="MsoPlainText"><span
            style="font-size:14.0pt;font-family:"Times New
            Roman",serif;color:#1F497D"><o:p> </o:p></span></p>
        <p class="MsoPlainText"><b><i><span style="font-size:12.0pt">*Cookies
                & coffee will be served in Room 122 at 3:30 PM<o:p></o:p></span></i></b></p>
        <p class="MsoPlainText"><o:p> </o:p></p>
        <p class="MsoNormal"><span
            style="font-size:12.0pt;font-family:"Times New
            Roman",serif;color:#2F20A0"><o:p> </o:p></span></p>
        <p class="MsoNormal"><span
            style="font-size:12.0pt;font-family:"Times New
            Roman",serif">Elle Wilkinson<o:p></o:p></span></p>
        <p class="MsoNormal"><span
            style="font-size:12.0pt;font-family:"Times New
            Roman",serif">The College of William & Mary<o:p></o:p></span></p>
        <p class="MsoNormal"><span
            style="font-size:12.0pt;font-family:"Times New
            Roman",serif">Physics Admin/REU Coordinator<o:p></o:p></span></p>
        <p class="MsoNormal"><span
            style="font-size:12.0pt;font-family:"Times New
            Roman",serif"><a moz-do-not-send="true"
              href="mailto:evwilk@wm.edu"><span style="color:windowtext">evwilk@wm.edu</span></a><o:p></o:p></span></p>
        <p class="MsoNormal"><span
            style="font-size:12.0pt;font-family:"Times New
            Roman",serif">757-221-3503<o:p></o:p></span></p>
        <p class="MsoNormal"><span style="color:#1F497D"><o:p> </o:p></span></p>
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